Handed over to legal department

My data contract which included a wifi router came to an end on the 16th of May 2018. I dont need this contract anymore, so I did my part. I phoned them on the 16th of April to give them a months cancellation notice. They told me that everything is in order and that my sim card will be deactivated on the 1st of June and that the last debit order will be deducted at the same time.

I checked my bank statement today and realised that they deducted an extra R155. I phoned them an hour ago to find out what the problem is. I have three contracts with Cell C, one voice, one data which is linked to my voice contract and then the contract that came to an end. I forgot the phone number and had to supply them with my ID in order to get information on this account. The guy I spoke to could not give me much information and he refused to supply me with the phone number. He then proceeded to tell me that I was handed over to their legal department and that I must phone them directly which, I tried for the past hour, it just rings.

I want to know why I was billed extra and more importantly why it was handed over to the legal department? I have never defaulted on my account and I did my part in cancelling this contract. Why must i waste my time in trying to get information?

PLEASE CAN SOMEONE PHONE ME ASAP!