Mondo and MTN a ****

I am actually up to my wits end with Mondo and MTN. I have numerous reference numbers but no resolution. For the 100th time, Mondo called me in Aug/Sept advising that they see I purchase additional data each month and because I had an additional data sim that is being used by my niece, I took 2 of those contracts. About 5 days later, a courier came to my door with 2 sim cards. I immediately told him that I did not expect any sims but just a contract and he told me to take it up with MTN. I would not have taken 2 additional sims because I do not have extra devices to insert these sims on. I called Mondo and cancelled immediately. That was still within the 30 day cooling off period and was told the sim cards will not be activated. I delivered the sims to MTN and to me this issue was buried. I was going through my bank statements in January and noticed that I am STILL getting billed for these contracts. I contacted the call center and think it was only in late February that the cancellation went through. I was then told to call MTN regarding the refund. I have been calling since March and have been given reference numbers but no resolution. Now I am being told that I need to submit the contract (which was never sent to me) to prove I don't know what. Mondo says they no longer have it on the system. I have however been paying for a contract I have not used and sim cards I do not have which I believe is grossly unfair. Could someone please assist. I have (in the last 7 days) received 4 more reference numbers.