(508) 542 in New Bedford, MA

This is my phone number! I'm doing a search on my own phone number because my Facebook account has been compromised. I used to use my phone for Two-Step verification to login. I would receive a text code and use that to log in. Facebook won't allow me to log in because it said my phone was "deactivated" from my account. I'm surprised to see it listed under someone else's name. I've had this phone number for years and purchased the phone itself on Cape Cod. What are my options to investigate why this number is attributed to someone else?