Horrible Service From MTN

I have had my number with MTN for over 20 years and in the past 3 years I have been using in on contract.in May I cancelled my contract and asked them to migrate my number to prepaid. instead they disconnected my number from the network and no one is willing to resolve this matter. I am in the job market and need my number to work, but they obviously don't care because my number has not worked for weeks.