If a purchase you made has not shown in the application after the purchase first try closing then restarting the application.

If this does not solve the issue it can be resolved by using the Restore Purchases feature in the settings menu of the app. 

For the Android version of Thumb Drift, there is no restore purchases feature as the IAPs are intended to restore automatically as you sign into a Google Play account to which the IAPs have been linked. 

If you use the Remove Ads button a second time - if you had previously made a successful purchase, neither the App store or Google Play will charge you again.