Took insurance for phone now they don't want to replace lost phone

I took a contract with Cell C which I was paying monthly for the phone and added insurance. I lost my phone last month and went to them to block the phone and to start process of me getting a new phone as I have been paying insurance for it. I have been there countless times and they say I did not sign up for the insurance although I know I did. So I have asked them to give me or send me my contract I signed initially so I can see that I did not take it but they are refusing to do that. I have called their call centre countless times and have gone to the Cell C store in Richards Bay without any help or solution to my problem. I am appalled by their service and behaviour towards handling my case, no one has called me back to give me feedback and I have to waste my time and money going to the stores or calling to find out what is happening with my claiming.