Account suspended without cause

My account was suspended by Mtn for no reason whatsoever. I always pay my account each and every month without fail but two days ago I received a msg saying my cheque was returned by the bank (I do not pay by cheque but EFT). When I called, the agent could give me no information as to why my account was suspended. I was told it would be re-activated, it is the next day now and I am still sitting without service. I called Mtn AGAIN, apparently, my request is pending so I must be patient. i kindly explained to the agent that the reason I do not need to be patient is the fact that I pay my account each month so I do not need to deal with this mess. If I were a bad payer, perhaps I would understand how a mistake like this could be made. But I am not, NOT once have I missed a payment! I was told by 9am my phone would work, it is 09:31 and it is not. The agent said she would call me at 09:00 to check if all was fine but I have still not received a call. I don't understand why as a paying customer, I need to call you Mtn, when you are the one in the wrong! I am beyond disappointed at the way I am being treated. What is the point of paying if this is what I get???