unacceptable attitude

I cancelled our contract with Virgin mobile in November 2015. It was a contract where Airtime was loaded at the beginning of the month and the debit was done at the beginning of the following month. The last debit for the contract is due on the 1st of Feb 2016. Today my wife tried making a call to me but realised she coudnt because there was no airtime but she had about R600 when she checked a few days ago. She called the cuatomer care line only to be told that the airtime was taken back and being withheld until the last debit was done. I called and was given the exact same story. I explained to the lady that that was not acceptable as i was being unfairly treated due to me cancelli g the contract. As far as i am aware it does not state anything in the contract regarding this. The lady Zininzi was very arront and rude. While waiting for the reference i asked my wife to take the ref no down to which the lady came back onto the line telling me to wait and have patience. Eventually when she did give me the reference i asked for her name and she refused completely. She eventually gave me her name. But i think this type of behaviour is unacceptable towards us who are paying good money.