MTN MAPONYA MALL

Greetings

I’ve purchased an Iphone7 on a R299/month Contract yesterday at Maponya mall. When i download myMtn app i just found out my bill so far is R362; i tried calling for clarity and i was told the amount is high because its prorated and according to how i understand prorata is “paying for the remaining days of the month” and that means i should be paying far less than that “bill so far” amount hence the remaining days of January is 11days. I wanna know as a consumer what rights am i having regarding this matter because i will never pay more than the advertised contract amount. Isnt this some form of false advertising? A consultant told me with mtn how the prorata works is that you pay your full bill and the other amount will be prorated which is whats happening to me she explained... the question arises; “if thats the case which means if i took the contract beginning of the month i couldve paid close to R600?” ...