Sim off for 5 day for no reason

I have a contract with Mtn and always pay my statement on time, just like this month and then all off a sudden it was just cut off, I have work to do with that number, people to call and waiting on people to call me and then it is just cut off, when I wanted to find out for what reason they did that they could not give me and answer how poorly managed are these systems then, so after a few phone calls and hassles with them they tell me that it will be working in 2 to 24 hours time I just need to take out my sim card, put it back in and it will work, so I'm on day 5 now and it is still not working. I almost lost my job because they could not get hold off me, non the less I got another statement from them on Friday but my phone is not even working what kind off business is these guys running. How hard can it be to just switch on the sim card number, This is really an unnecessary situation for no reason whatsoever. I need to know when this is going to be fixed Ref no *** and ***