terrible customer service

In 2014 I had been to the cell c branch in gateway shopping mall to buy my wife a Samsung tablet, I did take out the contract however I faced couple problems. Within 2 days the device had camera failure so I took it back in for the 7 day out of the box warenty but to my surprise I was told otherwise, the device was sent for assessment and I was told I had to take the same device away after 2 weeks of waiting. (y do they call it a 7 day out of the box warranty?). I refused to take the device hence was told I need to now pay a cancellation fee I was furious, I then informed the consultant that it must be cancelled and no funds must be debited but to my surprise the funds was debit for a device I didn't even have. I informed the consultant that I'm gonna reverse the debits and put a stop till my subscription fee is credited to me and cell c stopped my lines. I was under the impression that once the query is resolved I had to pay 550 rand and continue my contracts however I didn't know that cell c was billing me for the device and benfits yets my cards was inactive. I went in the bank to take out a home loan to find out I was black listed for and amount of 11000 I was shocked