When you purchase in-game valuables, there may be a delay between the payment and the moment you receive the purchase. If your purchase didn't come through, please wait for a few minutes. In case it doesn't help, reload the app page.
If after these steps you still have not received your purchase, please go to your Facebook Settings → Payments → Purchase History, choose the payment from the list and click on it. You should get a window with your purchase information: date, payment ID, transaction fee, total and so on.
Click "Download" in the top right corner of this screen to get a receipt file for this payment. Attach this file to the request ticket (link), and our support team will be glad to assist you.
If you don't see your payment in the Purchase History, it means that we didn't receive it as well. In this case, please check your card or phone balance (depending on what method of payment you used) to see, if you were charged for the purchase. If you were, please contact your bank or your mobile operator for further assistance.