Carrier that owns a phone number

Can T-Mobile find out which carrier owns or bills for a particular phone number? I ran a search on my parents that both have passed away and found phone numbers that they never had or used but is showing on a report background report. I'm not sure how or why these numbers are showing as them ever having them or why they are showing as once owned/used by my parents so I'm checking if T-Mobile can find out, if possible, fraud involved. I doubt very much they are even t-mobile has control of these numbers, but can they find out who the carrier is so I may contact proper carrier?