Mtn *****

Mtn is getting on my nerves now, my contract ended in June which i was paying R640 for a phone and data, they called to ask if I'll be upgrading and i said no I'm good i dont need an upgrade so R340 was supposed to be canceled then pay only R299 for data plan. To my surprise July bill was R900, when i called them they said its for services next month i will pay only R299 i said ok. Guess what August bill R1200, i called again hey what is going on here? They referred me from one person to the other Until the last one cut off my call still with no answer apparently no one knows what happened or why am I being debited so much money R900 extra, and i cant even dispute that amount because i dont want to mess my credit report. This is my last time signing up with them.