DTS Notification of Debt

I recently EAS’d and I just got an email from DTS saying I owe over 7 grand in debt due to valid debt from a duplicate voucher. This makes no sense because last year when I had to stay at a hotel for a few weeks due to an injury I was paid per diem, but I had to pay my GTCC debt. Roughly about $2500 from my own bank account (GTCC only used for hotel fees). What should I do? There was a voucher problem with my travel document and S1 kept telling me it was fine. Now I owe 7 grand??