Playmate WAS a word, in the sense of the kid down the street. But Playboy trademarked 'Playmate' in relation to the magazine.
You might as well have gone ahead and registered
www.thehunsplaymates.com so you could REALLY start a squabble. Of which one of them gets your head on a pole, first.

Might be interesting after they buried you, who would have won THAT fight.
You won't win this so why bother. Hand it over and learn something from it.

There have wayyyy too many precedences set for you to even attempt to go to court. You'll pay thru the nose and still lose in the end.