Uninformed $100 bill

I moved to a new place and signed up for a home internet subscription, and the call representative just arrange an installation for me and inform me I only owe $25 deposit an first month internet bill $50. The internet guy was here and ask me for the modem, I was very confused. He end up got one from his van and complete the set up. 3 days later I received a package mail to my property with additional modem and xtream box. I don't know what what are Xfinity trying to do. Is this a scam to try to charge me unused equipment? I returned the equipment and now the representative  said the $100 charge is for installation which I was never informed.

The issue is that nobody informed me of the $100 price that would be incurred for the technician visit. Neither the technician nor the customer service representative. 

This is ridiculous and unfair. It could have been an easy and clear set up but instead they confuse and distract me to pay $100 that I was never informed.

Please someone assist me to remove the $100 charge off my statement.