Canceling an order
When an order can still be cancelled.
Before it ships
Message the seller from the order page as soon as possible. A seller who has not yet dispatched the item can usually cancel it.
After it ships
Once an item is in transit it cannot simply be cancelled. Wait for delivery, then use the inspection window: if the item is not as described, open a dispute. If it is as described but you no longer want it, that is a return question for the seller — return terms are set by each store, not by the platform.
After the inspection window
Once the window has closed and the payout has been released, the order is complete. Contact the seller first; if that does not work, open a support ticket and explain what happened.