If you have purchased earlier and it's not getting activated in your app, please try restoring the purchase. If this does not work, then uninstall and reinstall the app and then try restoring the purchase again. This should solve the issue.
Apple Music tracks are DRM protected which means that we cannot get the audio data for enhancements. Hence Boom does not work with Apple Music. It is a technical constraint imposed by Apple and we cannot overcome this constraint.
Boom does not support these Music streaming services like these do not provide an SDK or API for integration. Boom requires access to the raw audio stream which these services don’t provide. So it is not possible to support them at this moment.
In app purchases are currently not enabled for family sharing. So you cannot share one purchase with multiple members of your family. We are working on enabling this soon, so please stay tuned.
You can cancel your subscription from the App store app. Go to your App store profile page in App Store app and check the Subscriptions list. From there you cancel your subscription. For more details refer this link