First, make sure that you downloaded the game from Google Play - downloads from elsewhere will fail with this error. Assuming that you did, this is an issue with the Google Play app cache - it's out of our control, but here are some steps that should help:
- Tap Settings, then Applications (sometimes just called Apps)
- Find Payback 2 in the app list, and un-install it
- Then, find Google Play Store, select it, then tap "Clear Data"
- Close Settings, then open the Google Play app and re-install the game
This will clear the cached data about what apps you own, and re-running the Play Store will download a correct list of apps you own – including Payback 2.
In some cases, you might need to reboot your device after step 3. Please try the steps as shown above before trying it again with a reboot between 3 and 4.