When a user is charged for a subscription or bundle, but they have not made a payment, you can choose to forgive that invoice. You can forgive an invoice through the Sales tab or the People tab.
Forgive Through the Sales Tab
Navigate to Sales, go to Invoices, then find the user you want to forgive the invoice for, and click on the invoice number. On the top-right corner, click on Forgive.
Forgive Through the People Tab
Navigate to the People tab, select which user you want to forgive the invoice for, and click Edit. Go to the Payments tab, and click on the invoice's number. Then click on the Forgive button located in the top-right corner and click on Forgive.
Note: It is not possible to delete an invoice however Forgiving an invoice to will make sure that you do not collect payment from that user.