Is there a way to enable port fowarding for buy a session?

So I have a Netgear lb1120 modem. And the sim card I have installed is linked to a buy a session. However I want the to have the port fowarding option available. Because for example my nintendo switch has a NAT rating of D, and my xbox one says double NAT. Even if I set the modem for a DMZ to be the router I have connected. (Don't worry that firewall stays on). I still get double NAT, and I heard is because AT&T blocks things like port forwarding. So is there a way I can get my port forward back by contacting AT&T or am I out of luck because I use buy a session and not the main AT&T website.