First, check that you are signed into Play Games/Game Center, by opening up the game's settings menu and looking for the sign in button (to the left of 'contact us'). If you are not already signed in, tapping on this should load up your previous data.

If this doesn't help, please contact customer support by tapping on the 'contact us' button at the top-right of this window. Please include a screenshot of your proof of purchase/receipt and the email address linked to your Google Play/Game Center account and we'll look into returning your items ASAP!