Deleted

It detects playtime for that game on your Steam account, so you will be unable to enter until that disappears from your list.

Tell support to erase it from your library

similar thing is now with space pirates and zombies, there's a free weekend so you can't enter those giveaways

Protip: Never use free weekend limited offers unless you are sure you will not try to win that game on SG later.

you have to wait a couple of weeks till its gone from ur steam account