Consistant bad service

I logged a service request with vodacom, to change my payment method from debit order to cash, they issue me with a ref number and tell me that someone would call me in 48 hours, no one calls me and now they say am owing, the service i recieve from vodacom tell me how little the value their clients. This is has been the worst cellular network experiance ever. First they dont debit my account on time, then i ask to move to cash, then they dont inform me that my request was successful