To Cancel your subscription
Go to your iPhone operating system Settings > [your name] > Subscriptions
Tap the SearchGPS subscription you want to cancel, and then tap "Cancel Subscription".
You can continue to use the premium subscription features for the remaining subscription period
You will still have access to any premium surf sessions logged whilst subscribed
To Delete your account
Make sure you are logged in with your SearchGPS account
Navigate to the Account tab
Select Account settings
In red at the bottom select Delete Account and confirm.
Note this will delete any saved data from your account