DFAS keeps rejecting annuity forms?

My father passed away at the end of March, and I'm trying to help my mom get her annuity set up. I sent in my father's death certificate; they claimed it was unreadable and to resubmit. I resubmitted and called customer service just to have the guy confirm it was readable. Same scan I originally sent, and he said it looked fine to him, so not sure what the problem was. Still waiting to see if they'll process it the second time.

Then I faxed in forms 2656-7 and W-4P, only for my mother to get two letters in the mail saying the 2656-7 wasn't signed and the W-4P didn't have her name, address, or SSN on it (not sure how they knew who it belonged to if it didn't have this info?). I pulled out the paperwork, and sure enough, the 2656-7 is definitely signed, and the W-4P is completely filled out. I'm not sure what to do at this point. Is this par for the course? They just keep making things up until you get tired of calling them and resubmitting things? Do I need to just call my representative/senator and get them involved? My father served for his whole adult life, and this seems like a slap in his face that they can't even process a couple of forms.