No response to MTN errors

Recently we had WiFi installed on our farm. This entailed cancelling a contract *** which was paid up and cancelled. Cost R3904.09 ref.***. We then took out a new contract *** which we found out was not suitable for our area and installation. We took it back and cancelled it within 7 days ***. We then took out a contract recommended by the installer, which worked fine. We now find out that our bank accounts have been debited monthly for both the above cancelled contracts. We have tried to phone MTN and have spoken to our local MTN branch several times. We have written to MTN. All to no avail. To cancel our bank accounts has all sorts of problems. I can only assume MTN is badly managed of just couldn’t care less. Robin and Karin Waite