XFi Complete Add-On charge - What is that for?

Moved here.

Hi there, @user_5xtljz! We are glad to go over your plan with you! xFi Complete comes with the Xfinity Gateway modem, unlimited data, and whole home WiFi assessments to ensure you have the best coverage. We can out with some new packages this year. They all include the modem and unlimited data so it may save you some money to change to a new plan.

Please send us a direct message with your full name and complete service address to “Xfinity Support”. To do so, click on the direct messaging icon located at the top right of this forums page.
 
Here's the detailed steps to direct message us:
1.  Click "Sign In" if necessary.
2.  Click the "Direct Messaging" icon.
3.  Click the "Start new conversation" (pencil and paper) icon. 
4.  In the "To:" line, type "Xfinity Support".
5.  As you type, a drop-down list will appear. Select "Xfinity Support" from that list.
6.  An "Xfinity Support" graphic will replace the "To:" line.
7.  Type your message in the text area near the bottom of the window.
8.  Press Enter to send it.
 
You can see how to send us a direct message here, https://forums.xfinity.com/conversations/guidelines/how-to-direct-messaging-within-the-forum/697ba1e570934d009185c514.