BAD SERVICE

to cut a long story short I have been having endless problems with MTN service provider. first the store messed me around to get my contract done now I am having issues with making calls. every time I make a call it tells me I have insufficient funds when I clearly have enough. every time I call the call centre my sim card has to be reset onto the network. this is unacceptable. I have had the same security pin code for years now every time I call with the problem they tell me my pin code is incorrect yet I change it back to the original pin with every call I make to MTN call centre. now I have another problem with names and numbers I do not no appearing on my phone. I call the MTN call centre, the agent tells me I need to call SONY.... this is a problem with the network not my phone. if its not a problem with terrible service at the stores its their agents that cant assist you or their network that is always having problems...... FED UP NOW!!!!