Over Useage

The is unbelievable!!! Same story here 2 50 something live in this house and we got the message in Nov, that we were going to go over, almost did, then December same message come January by the 7th we had used all our data. Come on!!!  Go to the Xfinity store and guess what, I need to use their router and get unlimited data, more money for Xfinity.  I'm sick to death if this company and how they get away with this.  Going to the store tomorrow, have them look at all my devices all my usage since using their router and document.  I will do this every week for a month if I have to then take back their router/modem.  Plug my own back in and start over.