Can you imagine if a company did this for something really important, like your email? Is there protection against this?
No. People call these "their accounts", but they don't own them. They only exist as long as the company allows them to.
But generally yes you can go to court. Historically people have done that with Google to figure out the exact ban reason (or to get unbanned) but that's often with Adsense / YT accounts where you have clear financial harm.