How to file complaint on bad customer service at Xfinity store?

user_oldan This isn't the experience we want you or anyone else to experience. To send a direct message, please click on the chat icon in the top-right corner of the screen, and select "Xfinity Support" to initiate a Direct Message. 
Click "Sign In" if necessary
Click the "direct messaging" icon or https://forums.xfinity.com/direct-messaging
Click the "New message" (pencil and paper) icon
Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line
Type your message in the text area near the bottom of the window
Press Enter to send it