Account in arrears even after the debit order went through

Firstly I have been trying to cancel my month to month with them for over a year now. Last month they did not run the debit order and my account fell in arrears, I called and emailed them to deduct and when they finally did they did not update their accounts. I have called, emailed and gone to their store at mall of Africa several times to have this sorted. Their service is appalling