DFAS claims I owe them over $20k

I received a debt notification this month from DFAS alleging I owe them $20,459.13, but there is no possible way this is correct.

Additional context:

I separated from active duty on 31 March 2022. In February of 2023, I noticed that my W2 was incorrect. The dollar values tabulated on my 2022 W2 would have been correct if I had been active duty of all of 2022. After calling the finance office at the base where I separated, I was able to open a CMS ticket dated 3 March 2023. This CMS case was escalated through various back offices that were never directly reachable via phone. I periodically called the Total Force Service Center to check on progress. In the mean time, an incorrect W2 for 2023 was also generated as if I had been active for all of 2023. At the end of Feb 2024, my CMS ticket was closed and my case was referred to the debt team at DFAS (office 3891). I received a written debt notification dated 9 May 2024 claiming I owed a debt in the amount of $20,459.13. There were 2 reasons given for this debt: 1) debt is due to over-deduction of federal income tax withholding and/or state income tax withholding paid in your behalf after separation to the internal revenue service and/or state taxing authority. You will receive the benefit of the over-deductions when you file your tax return; and 2) debt is due to payments received after you entered a no pay status due to separation as of 31 March 2022. These payments are as follows: mid-month payment of $3,113.87 on 15 April 2022.

I called the IRS customer service line last week and was passed around to several customer service reps. Everyone I spoke to indicated there are no W2Cs on file for me, and they had no way of checking whether or not DFAS actually over-paid the IRS money in the form of federal tax withholding.

I have opened a new CMS ticket, a couple askDFAS tickets, filed a FOIA, and initiated a request for review by the Air Force Board for Correction of Military Records. I think I am going to simply pay the debt now in order to avoid interest/penalties and hope to get my money back at some point in the future. Any advice?