If a payment has failed and you want to stop a future payment on it:
Navigate to the patients profile
Click on 'Invoices' and click into the one that you want to stop
At the top left, you'll see the option to "Stop Retrying"
Once you click that button, Hint won't attempt to charge the patient for this invoice!
If a payment has been scheduled to run on a future date and you want to stop it from running on that date:
Navigate to the patient's profile
Click on 'Invoices' and click into the one you want to unschedule
At the bottom of the invoice, in the 'Payment History' section, click 'Unschedule'
The invoice will now sit there until another action is taken.