If I am paying for 30 days, explain why you are drafting my account after 20 days?
If I remember correctly, Surety auto renews 10 days before the payment is due. This is so that there is no service interruption if there is a problem with the payment going through.
The above poster is correct. You can find the automatic billing details in section 4 of the terms and conditions page.
Automatic payments are run 10 days in advance of the due date to allow reaction time for failed payments or expired cards before the account would go to overdue status, as this is a pre-paid month to month service.