Yes, you did receive the acorns but you don't get a system message telling you that you got them. That's probably where your confusion may lie.
To test this, go post a comment to a plant in the database. If it's more than a sentence or two in length you'll see your acorn count has increased by one. Tiny one-line comments don't get acorns.
To see every way to get acorns click on "Acorns" in the footer.
