MTN poor service

Have 3 cellphone contracts of which 2 is due for cancellation and Mtn is refusing stating we are in arrears. We have been in dispute regarding the outstanding amounts for almost 20 months now. They promise to get back and don't. Husband is not able to sit on calls during business hours as he works n relies on emails as well. Their legel dept only work business hours and don't ever call back. We are frustrated as they are now charging higher for month to month continuation. We contacted ombudsman and they wanted correspondence between Mtn and us and further information of which we don't have due to MTN lack of assistance in resolving