********** by Mtn and Mondo

I'm being ********** by MTN and Mondo , they sold a contract sim card which was delivered and was never activated but they were debiting my Account, I called and asked them why are they debiting my account for monthly data on inactive Sim Card, They canceled a sim card and I had to pay initiation fee or what ever for delivering a sim card. I recently find out when I was applying for a Home Loan Mtn mondo has written my debt off which is I never had I paid what ever they say I must to cancel and it's affecting my Credit Profile. I need Mtn and Mondo to fix this and give something in writing that I never used their sim card it was never activated.