Someone had mentioned that they would like invoices to be voided when a service is canceled regardless of whether the invoice is past due or not.
See https://www.blesta.com/forums/index.php?/topic/10894-scheduled-canceled-service-not-removing-invoice/

The current setting that controls this behavior is Void Open Invoices on Service Cancellation

1. Add a selector below Void Open Invoices on Service Cancellation when that checkbox is checked
   • The selector should be labeled "Void Open Invoices Days After Due"
   • The selector should have a tooltip that reads, "If the invoice associated with a cancelled service is past due, it will only be voided if it is not past due more than the selected number of days."
   • The selector should have the options:

     Name	Value	Description
     -Any-	any	Any open invoice can be voided no matter how many days past due it is
     0 Days	0	Open invoices can be voided until their due date. This is the default value for backward compatibility
     1 Day	1	Open invoices can be voided until they are 1 day past due
     2 Days	2	Open Invoices can be voided until they are 2 days past due
     ...	...
     60 Days	60	Open invoices can be voided until they are 60 days past due

2. Update the tooltip for Void Open Invoices on Service Cancellation to remove the text "that are not past due".