Normally rewards for offers relating to Free Gems will pay out in minutes, but occasionally there may be a delay. If you have not received your rewards, they may take up to 48 hours to reach your account. If you have still not received them after 48 hours please contacts our ads provider Tapjoy, they will be best equipped to provide support for this. You can reach them via the following steps:  

-Open the In-game Store 
-Press the “Get Free Gems!” button in the upper left hand corner of the screen 
-Press the “Missing Gems?” button in the bottom right hand corner of the screen 
-You should be prompted to choose the offer you had trouble with, and seek help for the missing Gems.