No technical support and some contests don't actually pay the winners.
I participated in a Contest for the song Mi Amor by Anitta, JVKE, and Sam Feldt and was never paid for it.I'm still waiting on payment from a contest with the song want u by Noevdv. I also participated in contests before that and was never paid for it.
The contest site loses the entries that you post. Almost every time they update the contest leader board I end up having to put my entries back on the board. You never know if the contests you win will actually pay you. There is no assistance or accountability from genni.com or preffy.com. It's a great concept but very flawed. If they continue to operate like this people will stop using this app or taking it seriously or worse legal action could occur. Do better you guys.
Update: Shortly after posting this complaint they disqualified my contest posts and 1 extra post disappeared for no reason in a contest that I was currently in. They would rather be spiteful than actually care about the content creators that trust their site.