jxn

Its okay if some people do not want to become US citizens ya know. Lol

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

You paid a fee for the application to be reviewed. It was reviewed, and you don't get a refund based on not liking the outcome. It was properly denied.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

It's pretty clearly defined in the worksheet that goes with the N-400:
https://www.uscis.gov/n-400 -> https://www.uscis.gov/system/files_force/files/form/attachments.pdf
"Attachment A - Naturalization Eligibility Worksheet
I have been a Permanent Resident for three to five years...
I am married to, and living with, a U.S.citizen. [True]   [False] -> STOP
I have been married to that U.S. citizen for at least the past three years. [True]   [False] -> STOP"
 
This is how everything in immigration works. They verify eligibility before adjudicating the form, but it is the applicant's responsibility to ensure that they meet the criteria first.
What service did USCIS not provide? They determined her eligibility for the benefit being applied for, and adjudicated the application. Just because she was ineligible at this time doesn't mean they didn't provide a service. Was the review of the documents free? Was the interview time free? Somebody has to pay for it, and they're nearly entirely self-funded so it comes from the application fees.
Imagine the people who file for a spouse or fiance to come to the US and spend ~$1000+ and a year or longer on the process just to get a refusal.

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

I believe the instructions are clear enough that you have to have been married in the last three years to the same U.S. citizen and still married at the time of filing and adjudication.  Soon enough she'll be eligible for the five-year rule and you can avoid a lot of the three-year evidence.
 
I believe you're right that the timing should have been caught before being called in for an interview, but I don't think you're entitled to a refund. Being correctly denied doesn't mean you get the money back.
 
https://my.uscis.gov/helpcenter/article/3049

If it was needed it would be listed in the required evidence section of the N-400 instructions.  It's not listed on things to bring for the interview either.  
 
My guess is it's taken care of at the biometric appointment now.  

They want proof he is not the father because you presented a document to them (that you swore was truthful, and I'm assuming required him to do so as well when he signed it) that says otherwise and has a legal presumption attached to it. They will not take somebody's word at face value here, so now you need to comply with their request and/or get the BC fixed.