Is it ok to buy a used iPhone 17 purchased on 24 months contract off a UK network from eBay?

Hi folks, good afternoon!

I see countless deals on eBay about the latest flagships. One of them is purchased on a 24 months contract and have monthly payments due, but the device itself is unlocked. Checkmend shows no details about missed payments and everything is clean. It doesn't have details on contract either. Could it be the device is too new, or hasnt had missed payments yet and they just don't have full information?

The seller claims the device has been paid off. Is there a way to validate contract status instead of finding out the hard way after few months? I believe the device would be blocked from UK networks if the seller missed the contract payment. The online IMEI websites show the device is clean and unlocked, and doesn't show any contract status.

Is there a way to authenticate contract status from device IMEI?