Problem getting proof of use from 3mobile on SIM only contract

an1179

IPhone stolen 27 November reported to police & 3mobile
Claiming on Insurance I have receipt for purchase I have a SIM only contract with three, do not have the box the phone came in.

Insurance company have copy receipt (from John Lewis no IMEI ref on receipt) and three contract, they now state that they want proof of use or a photo of the box with IMEI code on

Apple account has details IMEI/Phone number etc but will not provide proof due to breach of Data Protection!

Three mobile want to see receipt with IMEI number to provide proof of use they actually provided me with the IMEI number off the contract when I phone them to report stolen

I now have 5 tracking numbers from 3mobile each time I phone to chase up they just send another tracking number which then delays the process further. They keep saying on chat/phone they want a receipt with the IMEI number on it Grrrrrrrrrr

Any suggestions to help me to get further with this probelm would be greatly appreciated