For any question or problem with Polarglow, email support@flyingwhale.app. Say what you tried and what you expected; a screenshot helps.
In the app, open Settings, then Delete my data. That removes everything our server keeps for your installation: its notification tokens, your saved places and your alert settings. Deleting the app also leads to it: our server deletes an installation's data when Apple reports its notification token is no longer valid, or after 90 days in which the app has not contacted us.
Polarglow Plus is managed in your iPhone's Settings, under Apple ID, then Subscriptions. Refunds are handled by Apple.