Refunding a Package
You cannot refund a package through the OfferingTree interface because the money is immediately disbursed into your bank account upon purchase. You can however refund the payment through your Stripe dashboard if you collect payments for your package through Stripe. Please refund the payment through your Stripe dashboard by following this help article from Stripe.
Refunding a Registration From a Package
If a client or student registered for an offering with a package they purchased, you can refund that package just like you would refund a registration payment made by a credit card. Visit the "Roster" page under the "Manage Schedule" section and select the row for the corresponding scheduled offering or appointment. A pop-up displays with details of the registration(s) and a "Manage" button to further manage the registration. If you press "Manage", another pop-up displays, giving you options to cancel the registration or just refund the package usage or payment. To read more about managing registrations, please read this help article.
You can also refund a package usage from the package details page. Read this help article for more details on how to do that.