Tech sticks me with $100 failed sik when it was a Comcast problem

We just did a move and transfer and spent 2 hours on the phone to get the phone and internet working. Told the lady to remove the customer owned modems because we were going to use the Xfinity xb10 they shipped us. She said she did. Can’t figure out why no dialtone. Decided to schedule tech at no cost (she tells me), and he shows up next day. Takes out the customer owned modems that I was told were already taken off. Dialtone and phone service is immediately back to normal. I get an email after he leaves that I get stuck with a $100 failed self install kit. But it wasn’t. It was a Comcast problem. And still missing tv channels the tech says would show up in a day. Need help. Comcast can you help?