If you have subscribed Premium through Google Play Store, the cancellation of the subscription must be done there.
To cancel your plan, open your Google Play Store App and in the top right corner, tap on your profile picture
Next, select "Payments and Subscriptions". Then, choose "Subscriptions".
On the new page, locate your Astrolink Premium plan. After tapping the application icon, you will be directed to the subscription management tab.
At the bottom of the page, the "Unsubscribe" option will be available. Select it and inform the reason for the cancellation.
The App will show that the subscription will be canceled at the end of the subscription period and no additional charges will be made.