No response from MTN

Several weeks ago I went into MTN at Clearwater Mall and then to the customer support as I was forced to "upgrade". When i was invoiced after the "upgrade" MTN charged me for two instalments though my previous instalment was deducted as usual. MTN has not responded and I am now waiting for them to deduct two instalments after their "upgrade". While I was a MTN a tearful lady slammed het invoice down at the same desk with the same problem. Does MTN really want this type of bad publicity for a lousy R438?