I did not get what i purchased in game

Hey guys i was playing a game called dino dominion when i decided to buy gold which is the in game currency. But i did not get the gold. I checked if my account was credited because i redeemed a 15$ iTunes gift card and it still had 14.89$ and when i checked it did credited my account because my account has only 2$ left! What should i do now? How do i get my money back?