CGNAT'd?!?!

So I'm trying to figure out a port forwarding issue I just started having today and my modem IP differs to my public IP (whatismyip sites).

Modem IP:  100.80.x.x
Public IP: 207.216.x.x

I've also noticed a slight latency increase (stream) most likely because of this stupid CGNAT.

How can I opt out? According to the internets, it varies with whoever you get on the phone? =/