A disappointed customer

I had a contract with Cell C for almost two years, earlier this year I received an sms that says my contract has been upgraded, then I asked myself how cos I never got a call from anyone at cell c, so I phoned them, only to find out that someone from them has added another simcard of data without my approval..... to cut the story short my original simcard was blocked because I refuse to pay for both of them, I only pay for 1 at hand, the other one I don't even have it...... this people add another contracts on top of the one u have, and force you to pay or block your number....... a disappointed customer