MTN ke ****

Been struggling with MTN network coverage. I thought my router had a problem as it had no signal. Reset, reboot, tried it all but still no help. Called their call centre ( struggled to get through), the consultant advised that they are experiencing technical difficulties but should try later. Well fast forward to later still same problem. Then O stopped paying them because I could nt use the router and sim. Send them an email to cancel the service, even today still no response. Havent used the sim in about 3 months, now they demanding payments from me🤔what am I actually paying for that I didn't use?