From the FAQ - Adobe Stock Help | Common Questions
If I cancel my membership, can I still use any unused licenses in my account?
No. You can use your available licenses as long as your membership is active, but you forfeit any unused licenses upon cancellation of your membership.
If there was a warning I'd lose all download credits when that happened when I cancelled, I missed it.
If I rejoined would those credits return so I can use them, or are they gone forever?