Attempting to understand the current issue.
- that 3rd of 4 semesters was not paid by AROTC to the university during a 4 semester scholarship in 2020 - fully or partially? Meaning they paid not one dime?
- But your son did graduate/ commission so is that bill to the university for that 3rd (first semester senior year?) outstanding or paid? Who paid it if it's paid - you? If so, why? Why is this now an issue in 2022 - is the university sending you bills or is this about getting paid back what you paid out for the Fall 2020 semester? Just be aware that down the line if not resolved the university may freeze his account, not provide transcripts or confirm he graduated or even come after him/ you as the guarantor - so agree with a need to resolve.
- did AROTC pay nothing for the third term of a 4 term scholarship or did they only partially pay for that semester?
- If AROTC won't cover retakes, did they pay for the rest of the semester courses 9/15 credits? You said it doesn't matter with confidence if these course failures occurred before he was on scholarship. Just a guess - do they consider that a semester your son took less than full time credits because the retakes they don't cover/ recognize took him below at least 12 credits, and therefore they won't pay for it since he is required to take a full course load? that's my without a full understanding best guess fyi. Where is your son's academic ROTC adviser in all of this - who approved his 4 year plan? What's the actual rule of what AROTC owes when this happens? Don't just state with certainty as if you know the rules - expressly find out. He should ask cadet command. https://www.cadetcommand.army.mil/contact.aspx
AROTC says we've paid all we will pay, and pointed to prior courses needed to be repeated. Did your son fail a fitness test or get on academic probation for a low GPA or not enough credits, such that he wasn't on scholarship for the semester in question? Certainly he would know that if so. Recommend you talk with your son and ensure you have the full picture here.
I recommend you step back and ensure your adult son takes the lead to resolve this. *You can behind the scenes do that with him, but correspondence should come from him, not you.
I recommend your son reach out to Cadet Command, the bursar's office at the university, and clearly document that what the need is - I would have your son present the contract, and ask the Bursar's office to absolve him/ you of the responsibility given the contract you had and to ask them for help to resolve this. they should take this up with Army on your behalf.
I recommend your son continue to reach out to the unit in writing (forget phone calls), and begin to copy the administration of the university and the PMS. Reasonably timebox requests for answers with 5 business days notice. "please reply by close of business on Friday, Janauary 21st". He should note he is disappointed at the lack of the professional courtesy of a full explanation or even a reply to your recent questions. But before you do that, get your facts straight in-house with your son.
This all sounds surmountable to resolve. Just make sure you engage the bursar and cadet command and be open to the fact that by taking retakes your son might have brought his credit count too low to get reimbursed. How you deal with that is up to you if that's the case.
If you can share answers to the details above it may help people form this forum further assist with suggestions. Good luck to you and please keep the board updated so this saga can be a teaching tool (or warning) for others.