Horrible service from vodacom

My wife has been trying to cancel her contract for months now, the account was payed up and we were told we will receive a reference number for the cancelation, never received it, now we are billed for another two months, vodacom staff can not allocate the call to the correct person and once the call is transefered the line drops, I am now fed up with this bad service and it costs more money because of staff not doing their work.