Account Suspended Again

I have been a customer of MTN for 14 years (mostly via Nashua Cellular). During October I started receiving SMS that my account was in arrears. I have been on a debit order for many years and my bank account details have not changed. My account was then suspended while I was on holiday. When I phoned the call centre they could no advise me properly and were not able to tell me why my account had been suspended. It was however reactivated. Several days later I received an sms from MTN apologising for the error in not debiting my account due to MTN technical error. I then continued to receive threatening sms about non-payment, as well as notification that my debit order had been terminated. I then received an sms saying my debit was returned unpaid - if my debit order had been cancelled, how is his possible. I then received a further sms today saying my account had again been suspended. Having had enough of trying to work through the call centre I went into a MTN shop who proceeded to call the call centre and basically give me the same message about unpaid debits - despite having an sms from MTN that it was their technical error. I asked how to escalate this and was told I couldn't.