I use VPN and I have no problems at all. Occasional e-mail warning of a new device, but that's it. Never got locked out. Can you provide a bit more info, including screenshots of messages/errors/login issues/etc, please?
Also, either provide your ID string (you can get it by clicking on it in the bottom left of the Help window) or specify which platform (Plarium or FB), server (The Pirate Bay/The Golden Coast/Sirens' Strait), and coordinates you're playing at.
[you can send any potentially sensitive info via private message to me]