damaged phone of which it is insured

I have bought a mobile phone at exact store in 2016.On the 25th of April 2018 my phone went off.And I tried to charge it only to find out its no longer charging,then took the phone to exact store for assistance on the same day as the phone is still under warranty and it has been insured. The store took the phone to Vodacom where they couldn't repair but made a quotation.In this case I needed the insurance to assist further in which they requested I make an affidavit of which I did so but today(2018/05/23)the insurance company called and wanted to know how did the phone got damaged my reasons are on the affidavit the phone went off. please help as im currently not having any means of communication