Bump!
Have the same issue.
In BC times I remember GM restored me item that was destroyed months ago. And now GMs can’t restore Skull of Impending doom (such important and nonreplaceable item!) that was accidently vendored or destroyed like 1-2 weeks ago. And looks like much players have issue with destroying this damn Skull.
Technical support fresh thread: Item restoration in WoW Classic and "Skull of Impending doom"