broadband charges

Who ever is thinking of getting the MTN broadband /4G service please think again. I took the 10gig 24 month contract for R979 per month and for the first 6 months i was billed this amount. After the first 6 months my billed escalated extremely fast and went to R4328 and now this month i have just been debited R10,745. I did not receive a single ams or contact to advise me of the bill going over the given threshold. I have been to the store and they said to me i used over the 10gig. which is impossible because it would mean that i would have to download 100 full length movies to reach this amount of data which is far from the case. I have taken the unit and thrown it in the bin and will pay out the 24 month contract and never ever deal with MTN again.