They dont take responsibility for their Negligence

Took out a contract on a Sony Dual C3 Cell Phone. The back cover of the phone came loose twice. I reported this to the Centurion Branch where I purchased the phone.I requested them to send the phone for repairs but their sales people refused as I pushed back the back cover on both occasions.When it came loose for a third time I took it to the Centurion Branch and then only they were prepared to send it to the repair centre.Now they claim I have to pay R2400 to repair the phone. Due to their negligence and refusal i need to be penalised by paying R2400. Sorry Cell C this negligence is for your account. I refuse to pay. I will take this matter to Carte Blanche , the consumer protection act, I will place a banner three times the size of the one in Johannesburg in front of your store for bad customer service,I will even visit Allan Knot Craig in his office. I have been with you for many years and this is not acceptable. I will stop paying for the contract and you are welcome to sue me.Own up that you were negligent and keep your customers happy.This one is for your account and dont keep me waiting.