Stop over charging customers because YOU are useless and cant do YOUR jobs!

After numerous phone calls and emails eventually managed to upgrade my contact in November, well thats what I thought, MTN never completed this, so got charged a massive amount for December and January. Eventually again after a number of calls and emails (bearing in mind I live in the UK) MTN sorted out the contact at the end of Jan, now I want the R3000 odd that was over charged for December and January! Why must I be charged because they did not do their job! But alas - NO ONE FROM MTN CAN EVER BE BOTHERED TO REPLY TO YOU! USELESS USLESS USLESS money grabbing corporate *******!