You can void a shipping label so that its cost will not be applied to your invoice.
The Void button is not available if:
To void a label:
To void a label immediately after printing it:
When you request a refund for Canada Post shipping labels, the postage amount is credited to your PitneyWorks® or Canada Post account. Your PitneyWorks® or Canada Post bill will list both your postage charges and voided shipping labels (credits). If you use a voided shipping label, the credit will be reversed and a “use of a voided label” penalty will be applied and will appear on your bill.
UPDATED: January 25, 2021