How do I get AirPods Pro serial number if the case was stolen?

My AirPod pro case was stole cause whoever did it thought the AirPods were in the case at the time, trying to buy another case but In order to do that I need to give the serial number which is one the case, it’s also not connected to my phone as I tried to connect my AirPods using my friends case and hit forget device.

so how do I get on contact with apple to buy a new case if I can’t continue without giving the serial number?

[Re-Titled by Moderator]