Most likely you have received your upgrade but you cannot see it for some reason. This can often be resolved by Restoring your Purchases. Simply go to the game, make your way to the title screen, go to Options and then go to Restore Purchase. You can also choose to Restore Purchases by clicking Play and then going to the Upgrade or Buy Gold options.
If that doesn't work, your payment may still be processing or there is another issue. Here is how to contact Apple, GooglePlay or Amazon regarding in-app purchases:
- Apple - iTunes Store: About In-App Purchases
- GooglePlay - Apps with in-app purchases
- Amazon - Amazon Appstore Information
Please note - if you purchased your original upgrade on an iOS device and are trying to restore your purchase on a new Android device, it will not work and vice versa. This is because Google and Apple are two different companies and their devices are not compatible with each other.