What should I do if MEPS continues to request medical records that don't exist?

Ryan Stranzin
Your best source of "How do I fix this" is your recruiter ...they deal with this kind of thing every day, or if not because they are new, they have co workers, or the station commander to ask.
In general
The burden of proof is on the recruit
If you told the recruiter (or MEPS)
"I had a bad back, but the Doc said Id be fine in a year and I am"
You will need to provide medical documentation from that visit (s) If none exist you know of, find that Doc and ask them to write a letter to that point.
If you can not contact that Doc (with significant effort on your part) Then you will need to see a new Doc, and have them confirm you do not have any issues, illness, damage related to what you told the recruiter (or MEPS)
If this is a medical condition MEPS discovered all the same applies.

It likely requires you to contact Doctors, hospitals and clinics at which you have been cared for. It’s find the records or don’t serve.

They wouldn’t ask for something unless they knew it existed. Just saying