> which was also inside their network
A phone number isn't like an IP address, the call isn't coming from that number and almost certainly didn't originate on the t-mobile network
The FCC recently reduced the amount of time some companies have to implement STIR/SHAKEN to June 30, 2022.
https://docs.fcc.gov/public/attachments/DA-21-1593A1.pdf
>The Commission recently shortened the extension for a subset of small voice service providers likely to be the source of illegal robocalls.
> which was also inside their network
A phone number isn't like an IP address, the call isn't coming from that number and almost certainly didn't originate on the t-mobile network
The FCC recently reduced the amount of time some companies have to implement STIR/SHAKEN to June 30, 2022.
https://docs.fcc.gov/public/attachments/DA-21-1593A1.pdf
>The Commission recently shortened the extension for a subset of small voice service providers likely to be the source of illegal robocalls.