This has happened twice from this company. Twice I downloaded games (Empire & Puzzles and Merge Dragons, two games I would have never downloaded except for an offer for gems for another game), completed the requirements of the offer and waited for the reward offer which never arrived. So, I contact their support. Their support form on their website is laughable, as it doesn't allow you to send a screenshot over 5MB (screenshots on my iPhone are over 10MB) and they don't accept .JPEGs, at least not the form I accessed through my phone. Their auto-generated email response was that my claim was rejected either because I downloaded the game before (which never happened for either game) or I didn't fulfill the requirements of the offer (another line of garbage). I send them proof that I had not downloaded either of these games before and a screenshot of my progress in the game, meeting their requirement. Again, an auto-generated email rejecting my claim. When you communicate back, you'll get a scripted response from them, stating why you were rejected.
Frankly, I have no idea what they are looking at when they rejected my claims but I know I met their requirements. I honestly believe they are changing the terms of the offer and then rejecting the claim thereafter. And you can send them proof all you want, they will still reject your claim based on some arbitrary nonsense. They claim it is their advertisers that are rejecting your claim but I call B.S.
I wish I knew who to contact at Apple and let them know about theese shady people.