Cheque Account

I had an account with standard bank and the account was inactive from Oct 2015 and eventually it was closed. Because there were debit orders going off in the same account, it was in excess when it was closed. Standard bank sold/handed over my account to ARA in 2016 in June. ARA contacted and I made an arrangement to pay off the account by debit order. They debited my account until Nov 2016 however when I requested a paid up letter I never got it. At standard bank it still reflects that I still owe them however the account has been settled in full. I just got off the phone with ARA, they say they are not able to trace me nor have any records of my standard account being handed over to them. I've been going back and forth trying to resolve this with no success. I'm really exhausted now don't know what else to do. Standard bank has again handed the account to NDS for collection which is another debt collector. Seemingly I'm been ****med somehow. The only proof I have available of that debit order is my bank statement.

Kindly help me **********