Bought MTN prepaid card for roaming in England

Last Sunday on the 12th April, I purchased a prepaid mtn SIM card for roaming purposes in England (i left for trip on Sunday) I loaded Card with two R180 talk time vouchers & 2gig data and activated roaming features at the store. This total transaction costed me R605. When I got to England that Monday I switched phone on and did a balance check to find talk time balance was zero. Also to make matters worst the roaming did not work for the entire duration of my one week stay in London. I had no coverage which was opposite to what the Indian guy at MTN in king Shaka store promised me, I called MTN 173 when I got back to SA and they told me I had accessed the Internet and it costed R350?????? I queried why the charge did not come off the data bundle as it was supposed to...???? This is utter bull as I had no coverage or roaming capabilities in London. I came back with the 2 gig data and was not able to make any calls in London. MTN has let me down royally. I want my money back as I did not get the service I was promised, this is a breach of contract. They charging my talk minutes for some \internet connection"that never happened. This is ********.....I never expected this Mtn."""