Lousy lousy service from MTN and Buy Mondo

In February I was offered an additional contract by Buy Mondo, an approved MTN service provider. However, I cancelled the contract before anything was delivered to me. Every month since then I have had to pay about R300 for this contract. I have phoned Buy Mondo many a time, just to be referred to MTN. MTN referred me back to Buy Mondo. Nobody accepts responsibility for the cancellation of the contract. This morning I was on the phone with both companies from 10:45 till 13:45, being referred from Peter to Tom and Tom to Peter, but my problem is still not resolved, I have never in my whole life been this frustrated by absolutely lousy, lousy service.