O2

I lost my phone last phone and reported straight away to o2, but my insurance company is asking proof of usage , and last time phone was used with imei number . How can I get that document For my lost iPhone 11? Thanks

I have trying calling o2 customer service , but with this covid-19 era , seems impossible to speak to someone , lost my phone last phone and insurance company is asking my "proof of usage" with imei number and last time my phone was used on that numb...