Check if Device Reported Stolen

¡Hola!  

I recently purchased an iPhone 11 on Mercari for $60, and found out finally after fixing it that there's an iCloud lock.  But I am also curios if there is any way to check and see if it has been reported lost or stolen through T-Mobile.  If so, I would gladly return it to the owner, or see if they did not wish for it back, could unlock it.  I know if I were to ever lose my phone, I'd pray somebody honest found it and did their efforts.  Does anybody know how I could go about that?