Technician fee

I am having internet my internet keeps coming in and out I can't even watch a movie on Netflix with it downloaded more than 5 times It's been like that for a month now. I call to make an appointment so a technician can come to check it for us but they didn't tell us how much they will charge us for it can somebody tell me how much it's would cost? We being we Xfinity for almost 4 years now.