Horrific billing

My husband had a contract with MTN. His monthly installment was R229 per month. If check his records,you'll find that he's always managed his account diligently and paid on time every month. October 2015 was his last month with MTN & cancelled his contract.In October he purchased a game for our son as a birthday gift and needed to download something from the internet to activate the game .He knew that he would have to pay a little bit extra for the download. He did the download overnight but the next morning the download was unsuccessful.Instead of the normal R229, we expected a bill of about R400.To our shock,we got a bill of R10 9053.53!!! To our dismay, we had to reverse the debit order, as we would not have had food to eat for the month!If you study our itemised billing, you will see that the majority of the data charged trying to download this game and it is really unfair to be charged this ridiculous amount to download a game, which never even completed!We acknowledge that we tried to download the game and that there were updates running in the background but to bill us R10 953.53? I am making an appeal to please review and reduce this amount.