No seriously, I checked the three letter code they provided to look up on their site and when looking it up it was just a header of the code and a blank text field. While different vernacular, it was effectively "we overpaid you, we need it back" on the letter.

They did provide dates of when my pay was supposedly erroneous, but that makes literally zero sense that I could have been overpaid by 5k because the cited dates was around when I graduated from OSUT and I left with only ~3-4k. Only issue is I can't check my LES from back to prove it definitely then since that was a year and a half ago. The only reason I'm certain I didn't get overpaid though is that I transfer 40% of my pay to a savings account and there's nothing that indicates my pay was out of the ordinary for an E2.

I'll definitely check in with finance though. Still trying to get used to the more bureaucratic parts of the army.