At this time, Optix does not support adding additional plan hours/usage (or refunded hours) to a user's account. However, there are two ways you can resolve these matters:
Add a discount onto an upcoming invoice. To learn how to add a discount onto an upcoming invoice, click here.
Offer a partial refund on an invoice they've already paid. To learn how to partially refund an invoice they've already paid, click here.
Note: You can either offer the discount as a standalone dollar amount (i.e. $10 off their next invoice), or partially discount an existing line item (i.e. giving them 10% off of their monthly plan next month).
Need more info on Invoices?