Noticed a few folks wondering about it so I figured I'd chime in. Strangely, you have to follow the official Payday 2 store page to receive the rewards. I tried joining the group as well as making sure I had linked my Nebula account, but neither of those did the trick. Once I followed the store page though, any community items became accessible. Hope that helps! Also wanna credit user diot coke for mentioning it in an earlier thread lol