Mtn southgate next to post office BAD SERVICE

I went to mtn southgate next to post office on 30 july 2019 around 9 and apply for additional line and the consultant by the name of Gontse promise to get back to me around 13h00 and he never did then i called him around 15:00 to ask for feedback and he said the application still in process i he will call the next day. I called him again today on the 30 july 2019 around 11h00 for feedback as since i went to the store he never bother to call me back and guess what, after i call him he is now telling me that my application was declined and i ask why and he say i am listed or blacklisted and i ask him to tell me blacklisted by which company and he say i must call mtn 135 and ask. I know my credit score then i called transunion and clearscore to check and all my credit is good and MTN approved my 40gig contract 3 month ago. So if i ddnt call i was not gonna get the feedback and i did ask the direct line to credit vet department but the consultant says we cant contact them. And the package i want it will expire today. MTN PLEASE ASSIST AND IF IM REALLY LISTED WHY YOU APPROVED MY 40GIG WITH THE ROOTER 3 month ago. Please help