Find serial number of iphone from dead iphone

Insurance company declining repair of iphone because they argue that the covered iphone is not the one that i am sending to them.

• sim card tray of iphone shows the correct imei.
• i dont have any itunes/finder back up.
• no icloud back up
• iphone is not on appleid.apple.com
• the iphone does not turn on at all so i can not plug in to the computer to find serial number.

the insurance company does not provide any proof at all that this is not the correct iPhone and do not tell us what is the serial number of the device that i am sending to them.

do you know how can i find the serial number of an iPhone if it does not turn on and i cannot do it with any of the adobe methods.