I got locked out last Friday afternoon, too. I saw that "prohibited country" message for an instant, too. After calling a phone rep, I was told my account # and login password (and screen name, perhaps, I forget) were found somewhere in the "darknet."
The phone rep said I had to get my PC "professionally cleaned" even though my 2 anti-spyware scans (Malwarebytes and Windows Defender) came up clean. This annoyed me a lot. I have also lost access to their automated phone system, as I can only speak to phone reps to get info or to make trades. That actually isn't that big a deal because I rarely initiate any transactions. So, I have done nothing to try to regain automated phone or internet access to my accounts.
I think Fidelity's request for me to get my PC "professionally cleaned" is overkill. It's a nuisance not worth the time, cost, and effort to get my access back. I have used internet access for Fidelity for only a few years so losing it isn't a big deal.
Fidelity mentioned a few weeks ago that they will introduce a new, extra layer of security for certain transactions. This can be entering a texted code to make trades, for example. That's fine with me.
If Fidelity wants me to make a new username or password, that's fine. If they want to give me a new account number, that's fine. But I won't haul my PC to Geek Squad or some other outfit and wait around all day (or longer) for them to "clean" my PC.
No kudos to Fidelity from me.