Bought new modem to replace your rental modem

@TristonWilli11 

AT&T is a rental only business model for the modem. Owning modems was for their legacy internet service which cannot be gone back to. And of course modem is proprietary, not shareable between providers.

So the modem (Gateway) you cannot replace and get rid of rental cost. Some choose to get their own router that may have better features, but that will still connect through AT&T's modem to begin with.