POOR SRVICE FROM CELL C

on the 24th of July I lost my cell phone which had a cell c simcard which I have ben using for more than 10 years.When I contacted Cell C to have my device blacklisted for insurance purposes I was sent from pillar to post.Eventually today I was told that the day my phone was lost I was not using a cell c sim card in the device which is totally wrong.My cell c sim is my only cell number.I had one phone which had my only sim card in it.The claim that I wasn't using the sim card on the day the phone was lost is beyond ridiculous.I am being prejudiced from lodging a successful claim over false information provided by Cell C.All I need is for Cell C to treat me fairly as a customer instead of giving me wrong information.