Incomplyance of duty due to not adding insurance to phone

My phone was ****** out of my vechile. I went to C Cell after I made a case to claim from Cell C insurance after submitting all documents Cell C said that according to their system I do not have insurance. I have my wife phoned insured by Cell C, and I for fact know I did ask for insurance for my phone I mean how won't you take insurance out for a phone worth 15000 rand, what do I do now as a customer against a company like Cell C no I must pay the same price monthly with out a phone because a certain employee of Cell C did not do their job correct I must pay the consequences and if you ask the number for somebody at head office they just give you customer cares number I hope this concern will reach head office