One-time $100 charge for installing a MoCA filter

I recently scheduled an appointment with a technician due to a problem with my ethernet connected desktop  being paused even though I have never paused it on my Xfinity app. The issue turned out to be caused by the MoCA connection on my gateway making my desktop visible to my neighbors, and it was one of my neighbors that paused it (reasonable, of course, who wouldn't pause a device they don't recognize).

The technician was incredibly helpful and simply added what he called a "MoCA PoE filter" to my Gateway and the issue was resolved in less than 10 minutes. I then checked my upcoming charges in my account and was surprised to see that I was charged a $100 one-time charge for this installation. After spending some time scouring the internet and Xfinity forum threads, it seemed to me that this is a common problem for buildings with multiple apartment units. I'd understand the $100 charge if the filter needed to be sourced first and other actions needed to be taken, but the technician literally had it ready in his toolbox and was installed just like that. Knowing that this is a common problem, I feel like these filters should be included in the installation package, even for a self-installation (which I did because it was straightforward enough) and not really the customer's fault, hence why I feel the $100 charge is unjustified. Looking back, considering this is a relatively cheap piece of equipment (found it for around $10 on amazon after the fact), I probably should have just installed it myself, but I wasn't sure if it would be compatible with the Gateway.

I just want to know if such charges are normal and cannot be waived. I'd gladly pay a service fee that is proportional to the amount of work done, but as I said, $100 seems much for a simple component that should have been included anyway. Thanks in advance for any assistance.