Ridiculous

MTN called me from there call centre to upgrade my contract which they did. I am on an unlimited contract and since they upgraded it I can't make any calls it has been a month now and bo luck. I have called mtn customer everyday since and no help. I have been to 2 Mtn stores and no one can solve this problem. I went to Mtn head office and they are closed due to covid. They debit my account religiously for there debit order yet no service. What do I do ??