contract not cancelled

Ref ***<br> In September we cancelled our sons contract to pre-paid. Two numbers. In October you charged us over R4000 for one of our sons despite receiving an sms saying he had been switched to prepaid in October. You have now charged us another R4000 in November even though he has been using pe paid for week over 6 weeks. We complained on Nov 13th. Nobody came back to us. Today we complained gain and were told that the deadline for the complaint expires today....3 weeks after the complai t was made and logged<br> Your service is absolutely despicable and you have now taken a further R4700 from our account when my son has been on prepaid for 6 weeks. You are absolute con merchants. My other sons contract was converted to pre-paid at the same time and that has been fine....so clearly someone forgot to do the conversion.....please respond.