Contract to prepaid nightmare

I did have contracts at One2One at TFG group for my children. I have cancelled the contracts on 19 July 2017 so it will be on prepaid from 20 August 2017. 21 August 2017 I phoned One2One about the sim cards not working, they said that MTN cancelled the sim cards and that we need to purchase and rica new sim cards so that it could be port with the same number to prepaid. After a few days still it wasn't working and I phoned again, they said that they are waiting for MTN to give feedback, still MTN didn't response to One2One. Today it's 31 August 2017 and still no feedback. MTN is absolutely terrible with porting and feedback and also very expensive. I wish that they could disappear from the network for good.