How to remove my name from the editorial board of a journal on Beall’s list?
The best way to deal with this is to get legal help. Keep a copy of all your communications (email, etc.) with the journal, bring it to a lawyer and state your issue. Legal help can be expensive, but if you're seriously concerned about being listed and consider a high priority to get off the website, then I advise you to seek quality legal help as soon as possible.

In the mean time, you can also make a note on your personal website/blog/social media/profiles/wherever people access you and your work that you are not an editor of that journal.