can receive calls - poor customer service (no response logging complaints)

since the 24th of August to date, I am not able to receive any calls. I can dial out but can't receive calls. I have phoned MTN customer care services numerous times and got ref numbers but the issue does not get restored. I visited MTN stores with feedback that they can't help only the call centre is able to assist with sim issues. i have sent emails but no response from MTN? MTN is collecting their monthly subscription fees but cant assist with sim issues?

if I want to cancel my contract I am told I am in breach but they can't fix my issues???????