bad service MTN and Mondo

I am so disgusted by MTN and Mondo. I did an online upgrade for my sister and they change her cell number to a router number without communicating or advising her of the changes. Its been over a month now trying to resolve this and they are unable to assist. They requested us to return the router and promise to cancel the contract upon receipt of the router and we did as requested, but still to date we have no joy on this issue, its be a serious headache. My sister still cant use her cell number and now they are telling us that they cannot cancel an upgrade. This is seriously not on and inconsiderate and it has caused a huge inconvenience.