I have joined and received nothing from the last drops, even though my link was successful
Don't know what is up with that

they require minimum 10 posts in the forum per week in order to receive airdrop (to prove you are active users). In your case, you did not post enough. I checked the status it says:
Skipped for the current coin distribution. We found 3 valid posts from 21st July, 2017 to 28th July, 2017. You must have at least 10 valid posts.you can check your status, there's a link in OP.