Losing all hope in MTN, Can't recieve any calls or SMS

I am very disappointed and lost all hope in Mtn, after one of my phone contracts ended in september and I was migrated to prepaid, my number *** is not recieving any calls or sms, whenever you call it it'd say number invalid. I called mtn call centre countless times but no one is able to help me. I'm losing a lot because of MTN incompetence and I doubt if I'll want to do business with them again.