That is entirely dependent on your seller’s refund policies. If they wish to do refunds, they may do that through the guide on the respective payment processor’s website. We have included links to the refund guides for Arcadier’s default payment processors, Stripe and PayPal.
Stripe: https://support.stripe.com/questions/how-do-i-issue-refunds
PayPal: https://www.paypal.com/us/selfhelp/article/How-do-I-issue-a-full-or-partial-refund-FAQ780
If they would like their inventory to be updated, they would need to change the status of the transaction to “Refunded” from their seller dashboard after doing the refund.