Hostile.
I’ve never contacted the FCC, but have contacted the BBB, the attorney general, and do web work for a government agency that does oversight of public facilities. I also worked on the customer service side of ISPs and other web services for years.
So I was interested in what customer/consumer expectations on something like this would be.
Usually when the question here is a simple yes/no, the details will provide a better guide as to what’s being asked.
To the OP, from working on the other side of these sorts of things, the ISP is basically required to get a resolution of some sort now. You can cancel, ask for the moon, or get your problem fixed and they basically need to work it out to some sort of end. I only mention it because they probably have an internal team that specializes in this sort of thing and they will keep calling/writing/mailing for longer than usual. It won’t just be one or two calls.
Good luck with it, I genuinely hope it works out to be worth all the trouble that came before.