Gateway modem

Hi there and welcome to Comcast! Thank you so much for reaching out to us regarding your modem concerns. @user_vygsvd, some of our new internet packages comes with the modem rental included at no charge for you. 

Concern moved here to the Customer Service help section.

I was told by an Xfinity employee that I could get an Xfinity gateway mod on for free. ...

"Free" is on overstatement. "Included with some plans at no extra charge" would be more accurate. They build the cost of the device into the cost of the plan, rather than listing it is an additional charge.