Mismanagement of payments

Our account have been settled, through our bank Capitec December 2019, end of January the JD group decided to put through their debit orders as well, now every-time it cost me money to reverse those transactions i have been receiving messages about i am behind on my account when it has been settled,one of the accounts has been over paid and its a struggle now after how many phone calls to get them to pay the amount back, not once did i miss a payment, but due to their mismanagement i get harassed through messages and phone calls of an account that has been settled, i have phone them again this morning to try and get the over payment sorted out but every-time it is a different story, please get me the assistance i need and someone who actually knows how to do their jobs.