If you purchased a Gold Drop, and received the initial gold claim, then it's definitely active!
You'll be able to claim your daily Gold Drop gold in the Daily Quests menu. Every time the Gold Drop is ready to claim, the quest for it will appear.
If your daily claims are going down, that's because you're claiming your gold through this Daily Quest, and you're most definitely getting the gold you paid for.
Please note that the Daily Quest represents the claim of your Gold Drop, and not additional gold as a reward for claiming it. Make sure to read all Quests and offers carefully to avoid further confusion!