restocking fee

Typically, stores will not refund open electronics at all unless it is defective. The ones that do are the ones that implement a restocking fee.

You can't take a brand new electronic item that works, use it, and expect a full refund. The value of that item has dropped considerably. Stores would go broke fast allowing that. Manufacturers make it difficult for stores to return used items unless they are defective. The stores could try to resell the item, but then people would complain they're buying used items at a new item price.