Telkom Mobile Poor network & service

The service is extremely poor to say the least. For the past 2 months my wife have been complaining about the same thing. Our SIM cards either they lose network completely or they say 'not registered on network' when we dial however, data connection is there (equivalent to GPRS). We have on many occassions called there so called call centre however, the agents are rude and are not interested in what we tell them. We have inserted our sim cards in diefferent devices and other network sims in our devices and established that our devices are working properly. Telkom mobile/ 8ta people do something about this or must we all (that have problems) switch service providers?