Revolving Account handed to debt collectors

My RCP account was handed over to debt collectors after Standard bank erroneously logged the wrong amount for my debit order. Without informing me, they handed my account to debt collectors because my account went into arrears due to incorrect debit amount. I eventually authorized the debt collectors on 23/10/2020 to debit the full.outstanding amount in order settle my account. The debt collectors have refused to carry out the debit order in order to gain more interest on my account. Kindly assist.