Mtn not doing their job

If I can I wouldn't even give 1 star

.... Today my services is been suspended again, I contacted them in December then they told me they haven't received payment for April 2020 so I've sent them the necessary proof of payments that it went of my bank. In June 2020 i asked for my account to be changed to cash account which them happened 2 to 3 months later, January I called again my service is been suspended again they haven't received my april 2020 payment (which was a debit order then) and again sent the emails with proof that it was paid at that time.... And this morning again my service is been suspended for the same reason again.... What do I have to do I can call till I'm blue next month will be the same again.... The people at mtn isn't doing their work....