Shocking Service and unapproved debits from Bank

MTN seems to have changed my contract from a Topup 100 to an open contract with a limit of circa R975. My bill for April was circa R1350 which just gets deducted off my bank account at the end of the month. <br> <br> It is impossible to get hold of them. I have been trying to phone them for other reasons for over a month now and the call just gets cut off. <br> <br> I have never seen such shocking service. <br> <br> The mobile number that is listed underneath is not the phone number in question - it's my contact number. <br> <br> The mobile number is ***