Their employee demaged my new cellphone unit.

I took my new cellphone unit (Blackberry Z3) to Autopage in Greenstone to have my new sim card cut and inserted as it only takes in a micro sim. I was assisted by a guy called Chris who cut and inserted the sim card. The problem started when my cellphone couldn't read the sim card. The next day I went to a Vodashop in Greenstone to purchase a new micro sim and did a sim swap. The sim card that was inserted by Autopage would not come out. I immediatley went back to Autopage and a guy called Harold tried to take it out using a pen and some wire but it still wouldn't come out. He then booked it in for repairs. After over a week I called to find out about the progress and I was told they managed to take it out but the sim card reader was totaly damaged. I was then told I would have to pay the costs for the damage. I went to the store and asked to speak to the manager and a guy called Keith came and asked me questions. He then said the sim card reader could have been damaged before I first came to them or unless I can prove to them that their employee forcefully or wrongfully inserted the card they are not liable for the demages. My phone is still with them and not fixed. Please help.