Account Dubble Every Month Since upgrade

I upgraded 1 May 2015 and since then I'm paying double for my contract.<br> My contract had to be R650 every month and since i signed the contract my contract but now i have to pay between R1100 to R1500 every month. Even if I pay the amounts I'm billed for my phone are being blocked.<br> I called Mtn how many times now and the only thing I get are there's no caller usage. The call center did put a caller usage on( that didn't help) . I called the shop where I did my upgrade as well they did put on a caller usage (that didn't help) the shop gave me a number to dial on my phone *141*5# they told me to put the limit on R10 and there won't be any further problems. I refuse to pay a amount more than the amount i signed for.<br> If someone can't help me to sort this out then I wan't to cancel this Contract. Cause I can just as well go Prepaid. I want This sorted. <br> I really don't have a R1500 every month to pay a phone.<br> I don't own a bank if Mtn thinks that every person who has a contact with them owns one.<br> <br> <br> <br>