At Batch, we do recommend to use tools such as Google play developer for Android or iTunes Connect for iOS that can give you relevant information about uninstalls.
Google Play Console
If Batch does not know the information on the uninstallation of your application, Google knows it.
All you have to do is connect you on your Google Play Console and find on statistics tab, the number of uninstalls. You can also check on the dashboard the number of installs and uninstalls for the last week, month or year.
iTunes Connect does not give you exactly the number of uninstallation.
but it can give you another information which is "retention". Retention measures the usage of your app over time.