The paid versions of our apps will never display any advertisements. If you ever see ads, then you're likely still using the free, ad-supported version of the game. When you purchase any game, a separate, ad-free version of the app is downloaded to your device. The icon of the paid, ad-free version has a golden (or yellow) border around it, while the free version's icon does not.
We recommend that you delete the free version after purchasing the paid app to avoid any confusion between the two!