ebay's not going to read this (and they couldn't understand what you're trying to say if they did).
You can't just "cancel a sale unless you want to forfeit your FVF's.
You have to send the buyer a mutual cancellation. Then they agree or don't reply. If they don't reply, you can close it after 7 days and get the FVF's back.
If they deny the cancellation, you're pooched.
Imagination will often carry us to worlds that never were. But without it we go nowhere. Carl Sagan