*********** and unhelpful

I have cancelled my contract with MTN and moved to prepaid. However I can not make or receive calls. I have called MTN 4 times already and still no help. I was told I can not speak to a manager and that I should purchase another sim card. I have had my number for about 16 years now. Changing a number is a big deal and I should not have to do that because of the incompetence of other people. This is unacceptable.