US Immigration from Morocco

I'll start off by stating I'm completely lost right now.

A few weeks ago I emailed the Consulate in Casablanca with a question. I was sent Login information for the CGI Customer Portal (I don't know what this is). Then I received another email asking for a scanned copy of my approval letter from USCIS. Today I logged in to see if my question was answered and there is a fee there. I'm so lost right now. What does this mean? When should I pay this?

What does it mean if my wife got a letter saying that our k1 visa application is expired while we are waiting for an approval on our cr1 visa? Will this slow the process of our spousal visa?
( It will be 7 months on October 4th since we applied for the cr1 visa)

my husband his interview in 1st of October , he needs to have his medical exam next week , we try to call the 3 doctors that the embassy provide us on website, everything its fully books ,this morning he called no one answer the phone , I don't know if there is anyway to contact the doctor ?

AFFIDAVIT OF SUPPORT FORM(I-864,I-864EZ,or I-864W)

witch one i need to fill up for my wife for nvc and do i need to upload it or i need to send it in the mail with tax return thanks

please if anybody went through this process i need your help!

This last few months been chaotic just moved to Germany and had a baby and last thing i want is my case to get denied so im trying to gather as much information as i can before submitting my documents.

So all i need is to fill the Form I-751 + evidence + passport pictures + finger prints and the money is that all? Or am I missing something?

Also when I was reading the instructions mentioned that the adress need to be US adress. Can I still use our PAO box here in germany or it won't be sent to it?

Any reply is very appreciated.

Thank you!