Absa not honoring payment arrangements

I have a personal loan at Absa which I struggled to pay for a couple of months and was subsequently handed over for collection. Ever since then, I have been making arrangements with a collection agency, yet ABSA STILL attempts to debit my account for the arrears amount on my ABSA cheque account. Now, due to this, I have changed banks, but the problem is that I am getting harassed that the account is more than R4000 in arears. I would really like to understand from Absa on how they hand over accounts and then continue to debit and how they allow a cheque account to be that far in arrears. This is my last attempt at getting answers from Absa as the countless branch visits proved fruitless.