Telkom Insurance repair voids warranty on iphone X

I activated insurance on my iphone X handset when I renewed my telkom mobile contract. About 15 months into the contract, September 2019, my phone fell and the screen and back of the phone shattered. I took the handset to the store, as per instruction by Finrite, to process the claim. Important to note that I enquired if the phone will be fixed by an Apple authorized technician in order to maintain the warranty. The agent at the shop indicated that the handset will be fixed on discretion of the insurance on Re TC023925 After about a month and payment of the maximum excess, I received the handset. As previously experienced with the handset, it still had an intermittent "Ghost touch" issue, apparently experienced on some iphone X devices, covered by a recall for fixing by an Apple authorized technician under warranty.... Yesterday I took in the handset to istore in Canal Walk to fix the "ghost touch" issue under warranty. I did inform them that telkom insurance has fixed the screen and back of the handset. The phone was tested and confirmed that it had an issue, leaving it there to be fixed.... On arrival the istore agent informed me that the handset was not fixed with the following written confirmation as reason that void the warranty: "device inspected, found 3rd party modification and workmanship. Due to this Service is denied. Returning as is" The agent from istore confirmed that apple has void the warranty on this handset and will not work on it. I phoned the Finrite call center this morning and spoke to Katlego Dlamini, who indicated that she will forward my issue, first to the repair center and then on my insistence to the person in charge to respond to me. I am being brushed off by the call center after my handset has become a useless brick....without back-up service.... I insist on replacement of my handset as a matter of urgency as I use my phone for business purposes. Telkom Insurance has not responded till now