Damaged phone

I sent my phone in for repairs about 3 months ago, but got it back damaged. The manager of the shop then sent it back to have the damage done by the store repaired. He did not give me a new job card or number. Later I received a sms asking I must pay R2800 for the repairs, but the shop damaged my phone. Why must I pay Cell C to repair their own mistake?! I then went back to the shop and spoke to manager, he would have sorted it out and come back to me. Up to date I have not heard anything back from him and I do not get any further feedback. I don't even know where my phone is!? I refuse to work with the store further regarding my phone, because the service isn't poor, there is NO service!!! My contract is paid up to date, but I have not used the phone for a year of the contract time. Cell C just *****s my money!!!