MTN

I recently app**** online for an upgrade with MTN for my cellphone as I work in the medical field and it's difficult to get away. A courier brought the phone to me. At the end of the 1st month, a bill came for R7000 which is totally absurd and I queried this. We use wifi this is unexplainable. The month to follow another bill comes for R9000. I am told to pay it as it us reflecting as data usage in itemized billing. I reversed these payments with my bank as MTN cannot explain these amounts. Completely ridiculous!! Now this has affected my credit rating with the transunion bureau.