@LandonL
Without getting too deep into the morass of the telephone system. There are two numbers associated with a telephone line. The number you reference (4048005967) and a thing called the LRN (Location Routing Number). The LRN tells other telephone companies how to route calls to your number. A "port-out" / "port-in" is a change to the LRN.
When a telephone company puts a telephone switch into a LATA (Local Access and Transport Area)--basically a geographic area--, they are issued a LRN and will "own" a 10,000 block of numbers. Of course, other telephone companies can claim 1,000 blocks of numbers within that 10,000 block. That LRN tells everbody where to send the call for completion.
Intrado in turn serves a number of telephone companies (CLECs) and they internally manage where an individual number goes
I've lost access to the online tool that will tell me the history of port-in/port-out for 4808005967, but I can tell you that it was initially issued to Intrado and still belongs to Intrado. Without the full porting history on the number, it looks like Intrado may have screwed the pooch and given your number to someone else.
The bit that it was ported-out in 2021 sounds like complete BS, if it was true, you would not have been able to receive any calls on that line since November 2021 (I'm sure you would have noticed)
Maybe somone reading this will have access to PortPS (the online tool) and can confirm the porting history