Switching Cheque to Savings account and Absa loan

Absa has been trying to change my cheque account to savings since I have moved my salary to another bank. And absa loan has been sending debit order to my account even after telling them I will pay by cash. This has resulted in bounced debit orders, amounting close to R1000. Today I have just paid them, to put my account in positive so that I can change the account type, but all of a sudden the system doesn't what to change the account, it is still says it's in the negative through there is money in the account.