If the issue is your PTO after your notice, an employer does not need to let you use PTO after you provide notice you are quitting/resigning. Therefore, if the overpayment is for PTO you said you were leaving employment, they would be entitled to recover this money. (An employer does not have to respect the notice period you provided; they can treat your notice you are resigning as effective when you provide it. Also, employers have the right to generally bar the use of PTO when itis inappropriate--and it is inpappropriate to let an employee who indicated that he or she is leaving to be paid for not working.)Therefore, it appears you do owe the money and are liable for it. You should work out a payment plan or schedule to avoid possibly being sued.