Mtn number not working

I'm so disappointment on mtn I was on contract and then when I changed to prepaid they failed me .I'm unable to use my number any more went to empangeni branch several time and also in Richards bay .I have been using this number for 15 years I can't use it anymore please fix it my contact details is *** which I can be reachable on. Mtn please sort this out because I will be writing reviews daily on hellopeter I want my mtn number back which is ***