Poor service

I have 3 contractors with MTN and I wanted to change one that the contract was done to pre paid. I went to MTN vaal mall and I was told to call customer service for 2 months when ever I tried I couldn't go through until I went and fought with them that they must make the call , I think it's because on the options they ask if you want to terminate the contract if I say yes I struggle to go through , at vaal mall I was able to do that and I was able to change it to pre paid. I also took one for my father all of a sudden he is not receiving the data, went to vaal mall and they said I must call customer service again. But when I want a new contract they will help without me calling their customer service also their data does not last. I have been using MTN contract from 2002 but I am done with them