Elderly parents lost home phone number

Scammers ported my disabled parents' home phone number without their permission on 10/18/2023 (it was a digital line). They had the same home phone number for over 50 years so now all of their contacts cannot reach them, including doctors and pharmacies.

The scammers initiated a porting request, conning AT&T into believing the request was from my parents. They were successful, my parents' AT&T account was closed and now their number is with Metro PCS, tied to a scammer's iPhone. Multiple family members have talked to multiple reps with both companies and got nowhere. My mother is devastated because it seems hopeless to get resolved. She was recently in the hospital and could not call my Dad at home to let him know she was OK. We filed a case with the FCC over a month ago but have not heard anything. What can be done to get their number back ASAP from these criminals?