How to get an XB10?

Hello, I stopped by my local Xfinity store to try to upgrade my router to the XB10 and they didn't have any in stock. They directed me to call but I can't seem to get through to a live agent easily. I have, what I believe, is the highest speed tier and would like the XB10 to take full advantage of it. Can you please advise how I can get one either shipped to me or my local store? Thank you so much in advance!