Cannot add unlimited data option to plan
I'm using 1Gig plan with my own modem. I want to add unlimited data option to my plan. I tried activating it with this link https://www.xfinity.com/buy/plan/checkout/XFINUDAT but it always ends with this error
The product you’re interested in isn’t available for purchase at this time.
Get updates about Xfinity Home, Xfinity Cameras, and 24/7 Video Recording.
Please help! Thanks in advance.