Billed $100 for a technician without approval of the fee

Early July the call agents couldnt get the change of address switched and couldnt activate my new service address over the phone, so they told me theyd send a tech guy and it was required. And i set up the appointment with the tech guy over the phone, and approved the service appointment via a link the xfinity call agent emailed me. No where in my calls with them or the emails they sent me or the linked approval i approved did they disclose it costs $100. That is straight up unfair. Ive called several times when i saw the unexpected charge at the end of july. Ive been able to get $40 credited back to me. However the rest of the charge is just plain wrong too. The most recent call agent tells me when you approved him coming, you technically approved that fee. No i did not. I approved his visit, not his fee. You cant say i approved a fee if you never disclosed the  fee before or during the visit. That day the tech came out, he was running in and out of my apartment saying he wasnt sure what the problem was and was still working on it cause the building has xfinity service. And then while he was going in and out, i tried changing my service address one more time since the call agents hadnt tried in a few days after we failed the week before multiple times. The service address changed and the internet literally worked quickly after. Later the guy came back in shortly after and i asked hey did you fix anything out there, was there anything wrong and he’s like no im figuring it out and went back to rifling. And then i browsed a few sites to confirm the service and i showed him,  hey i got it to work. And he’s like oh youve got it, its fixed okay ill leave. I asked him, so what did you do? what was the problem(s)? and he just gave me weird look and shrug and eh noise and said bye and left super quick and in a rush. 

to my knowledge he didnt fix anything, he just went in and out of my apartment for 20 minutes.

according to this past forum post and official answer by an xfinity support person, i should not be charged for this visit. 

https://forums.xfinity.com/conversations/billing/professional-install-dispute/604cc2a6c5375f08cdc016ba?commentId=613fe83c16396f36267e688f

1) why do the xfiniTy call agents try to tell me i did approve the fee? I did not. I asked them what email and what paperwork and what proof they have with the fee info before or day of the visit, not after. They said i just technically did approve it when i allowed the technician to come via the emailed link to schedule him. That link and the site it took me to discloses no fee information. That is wrong and not real approval or consent, what they did and do with technician fees.

2) why am i being charged if he didnt have to actually repair anything? I set up the modem and router and cables myself each place i move and he had no part in that. if it had nothing to do with my hardware or cables or wires, they cant charge me with any actual services done.

my roommate has had similar problems with them and cancelled xfinity, because the dont disclose fees before or during the event and then bill you weeks later for it. 

I want xfinity support to address this fairly, which they have not these past 2 weeks.