Cell C do **** people

On February i ordered a phone from cell c, they took all my details including bank account details, they also promised that it won't debited before the phone is delivered and swiping my during delivery.... Then later they wanted to bill for what they didn't deliver, i called them and was given a runaround, i then went to my bank and removed the debit, but now when I check my credit score, I'm now in debt review and my credit score is bad. Now that I promise to open a case against cell c, they call me daily wanting me to go and make an affidavit and that say I don't have a contract with them and they claim that i was being ****med, when I ask them how am I ****med if when I contact cell c direct, they know that I did order the phone and it was not delivered instead they asked me if I need to insure that phone they never delivered... So they don't want to take responsibility and want to brush it off, I was thinking taking it further to teach them a lesson.