MTN horror service

I've had a particularly frustrating experience with regards to canceling a contract. I had a contract with them that expired in June. I had communicated to them before it expired that I will not be renewing or carrying pn with it. Yet despite that here we are 4 months later, countless calls without response to their call centre, emails that are attended once a month. To say your contract will be terminated on said date yet low and behold every following month you're issued a statement. You're essentially bul**** to pay despite receiving no benefit or assistance from them because you're credit score will be affected negatively