Offers completed within the Offerwall (which is what we call the offers you'll find when you tap "Earn Free Coins" located under the Free Coins section in the lower right-hand corner of the game screen) can take up to 48 hours to payout properly. 

At this time, the best way to receive support for this feature is to report the offer directly with the company we partner with directly (Digital Turbine). The easiest way to do this is to select the offer you're interacting with and to look for the "Having Issues? Click Here" message located at the bottom of the page. After you click that link you will be prompted to submit a Support request with Fyber by providing your contact information and a brief message explaining your reason for contacting them.