Insurance claim declined

I lost my phone Samsung A32 last year and i couldn't claim because i misplaced the box with IMEI number but i call and enquire on what what to do to claim if i don't have the IMEI number the consultant whom i spoke to said they can't assist me without the IMEI number now i found the box with IMEI number they are not approving my claim whereas i have informed them or spoke to them about the problem i had, i don't know what to do the number in question is ***