Being charge for international data that I did not use.

Xfinity is charging me $220.00 for the data that I never used. 

Upon arrival in my Dubai trip, I activate my travel pass. But apparently, my roaming is not working. So I contact their customer service and mention that my data roaming is not work. The CSR clearly mentioned that my roaming will not outside US because I did not turn on my roaming before I leave my house. And now they are charging me 220 dollars for roaming. I keep on contacting their chat to dispute and nothing happen.