Selection for free collection

Your assets were only nominated and not necessarily selected for the free collection.

There's no guarantee that any of your nominated assets will be selected into the FREE Collection. 

Stock accepts only about 10% of assets. 

See Free Collection FAQ:

https://helpx.adobe.com/stock/contributor/help/free-collection-contributor-information.html

Nomination and selection for the Free collection is an annual event. If you've already been paid for this year's selections, the campaign is over and you'll have to wait until next year. Adobe usually selects only a small,percentage if the nominated assets.

Well, first of all: Adobe does rarely use all of the proposed assets, as they want to equilibrate their free offering, and they want to avoid killing their for pay offers. So the competition is tough also here.

Second, if the images are still pending, they can still be included at a later stage. But if the selection process is over, you will need to wait for next year and may be they will include your asset again.