Packet switched data Calls

Hi<br> <br> I have e-mailed, phoned etc a couple of times. We were previously with Nashua for a couple of years. Since the contract was sold to MTN this bill increase monthly on the Packet switched data calls.<br> I do not understand how it is possible that this phone number's usage can increase all of a sudden since MTN took it over. I believe the billing is incorrect and not valid. MTN claims that the data was finished and they have billed us from the airtime. I still believe that there is an error on MTN's side as this bill has never in the pass 2 years over R500. Now all of the sudden since Feb it increases monthly with July at the highest - Double as what it used to be.<br> <br> Checking the data every month (oh and here they first said that this contract doesn't have and then all of the sudden it has promotional data - which it never had in the past.) before the billing period ends, it shows that the contract still has plenty data. This was Checked 30th we were billed from 26th. Customer Care is useless as you holding for 20 minutes and then gets cut off. <br> <br> Doing some research, I found that I am not the only one with this problem. <br> <br> Is MTN overcharging their customers? <br>