Internet slow down every day between 11:30am-2pm

I live in SF and just got Xfinity internet last weekend. Every day betwqeen about 11:30-2:00pm the internet goes down or is slow. I reached out to chat support and they are sending a technician. However i then got an email saying it will be $100 on my bill for the technician. This was not explained. I need my internet fixed as promised and a refund / credit for technician.