I owe more than my bill breakdown

I was trying to update my plan to include unlimited. (Which, I can't do that either, I guess I have to make a separate forum post for that because there doesn't seem to be another way to contact anybody?) I can't click "next" on the Customize Package page, so it won't let me continue adding unlimited data with the modem we already own, fine, we might have to get a new one whatever. But when I click on my cart in the bottom corner, before updating anything it says I'll owe $108.85 with my current plan. When I click on it, however, it only shows me the $97 for the internet plan and no other charges. I tried to look at a bill breakdown on the normal account page and it just tells me what my bill is, not an actual breakdown, and any links that may lead you to believe it will break down your bill give me an error page right now. I would also like to add that on the Customize Package page, if I select "add an Xfinity Gateway" then re-select "no, use my own modem" (essentially refreshing the cart) the cart total goes back down to $97 ($99 with autopay/paperless billing discount). Why is my bill more than described in the cart breakdown?