Dropped calls, no service

How is it that Telkom still has clients? It's unreal how things just don't work. Been instore 4 times in 1 week and each time, each consultant does and trys something completely different from the last yet Nothing works. You cannot call anyone because the cellular customer care just doesn't work. I have the worst signal, my calls don't go through instead I get numerous missed called sms's. It's just outrageous. I have even gone to the extent of doing a sim swap, still nothing. Worst services provider I ever been with.