GregC2015

It is no worries, it could be for something small. Who knows. Like the others have stated, you will find out what you need to do in the letter. Follow the instructions, take it seriously and turn it in quickly. Just a minor speed bump. The whole process is really quick, from initial filing to interview. You will see. It feels like forever when waiting on that NOA2, but it comes and goes so fast.
I did not receive an RFE during the i-129f filing, but did receive two RFE's on the i-864 form during the AOS filing. One was just a completely boneheaded mistake on my part. I filled out the house hold size wrong. I did not read thoroughly. The second one was because I did not submit the IRS Tax Transcripts with the filing. I did not do this for the i-129f and passed, but failed on the i-485. So now I am waiting on the outcome of submitting these corrections to them. Ordering the transcripts are easy BTW, just log on to the IRS website and search Tax Transcripts, go through a couple of questions and they will mail them to you. I received mine in five business days. Easy.
Again, no worries. If you need help, we are here.

Absolutely correct. One has to be in command of their own fate and not just assume others care about your life. To them, it's just a job, to us it is an amazing life waiting to happen.
Personally, I have met the most amazing woman ever. I have been searching for over ten years for this type of woman, and now that I have her, no amount of red tape or government bureaucrats is going to stop me. She's well educated (RN), magnetic personality, hard working and looks like a model to me. I felt like I knew her my entire life. I knew she was it the first thirty seconds of meeting her in person.
When I receive noa2, the nvc is going to get really sick of me. Starting at about day five, they are going to receive many phone calls from me
I've already memorized most of the information on here, and have directed and coached my fiancé on everything I have learned from this site, and everything that she will need to do. Everyone should be doing the same.
Focus, tenacity, victory.

I sent mine out on the 15th, two days before the OP and received my NOA1 hardcopy January 4th. The mail ran slower, but it didn't come to a halt. I tracked my package every day from the time I shipped it out to the time it was delivered. That tracking number is critical and should have been treated like a piece of gold. I would start making phone calls to the shipper and uscis to see if the package can be located, but the OP might just be SOL. All they can do is wait and hope, if the shipper can't track without the number. Good luck to them.