Despite the cheery paypal ads it is a complete pain in the backside. Many stores will not allow you to return items to store if you have used paypal. You can only exchange or have a giftcard, even if the item is faulty.
Only way to get a refund is to send it back via the post and wait weeks for the money to be refunded to your paypal account. You can then transfer the funds to your bank account. Complete pain in the backside and even more annoying as the items returned to store are taken to the same place as the items returned by post. No reason at all they can't at least let you return the item to store and then process the refund when the item reaches the depot. But no, you have to waste your time standing in a bloody post office queue instead.