Refund on supposed to be canceled account

I had ended an account back in Dec 2015 and opened up a prepaid account right after. The ended account still was getting charged to my bank account and for the last 5 years I was under the assumption it was my newly opened account due to them getting charge to different credit/debit cards. The total charges that I have been paying for the last 5 years total out to $3,000 and I would like either a refund or a credit to my current user account. I called and was directed to both the billing and retention department with no help in getting this resolved other than getting patched through to the wrong office.