Query if user is eligible for refund, or alternatively time spent in application.

Hello,

We are interested in tracking whether or not a user is eligible for a refund of our app. Is there a platform API call we can make to get this information? Or, alternatively, is there a platform API call that tracks the total amount of time a user has spent in the app? There are ways to track the time ourselves, but we would have to take extra steps to ensure that users do not hack the time, that the data is not lost when the user uninstalls the app, and that time played on multiple devices is included.

Thank you!