MTN -Unable to investigate properly and give my refund

Guys, do not buy airtime to purchase google play vouchers, what MTN does is they deduct the airtime, and then bill you again at month end, if you contract

I have been struggling to resolve my case with MTN, they are like refusing to check if they billing system is defective

firstly the contract was fine, i purchased airtime it was subtracted, then when i upgraded to their lower packages as my contract was almost done, this started happening and they refuse to check whats the issue and refund my money

all they say is you a loaded for content charges, they dont want to look further then that and now i am losing my money