Can a PayPal Refund Be Stopped?

Canceling a Refund: Not an Option
PayPal doesn't let you cancel refunds that have already been issued. This rule applies to both individual PayPal accounts and PayPal accounts held by organizations or businesses. Once you've issued a refund, you have no choice but to let the payment go through. At that point, you have two options: You can either submit a new money request through PayPal -- this means launching an entirely new transaction -- or you can ask the individual who received your refund to return it to you.
Canceling a Payment
Although PayPal doesn't let you cancel a refund once you've issued it, the website does allow the buyer to cancel a payment she's already sent. Click the 'History' tab under the 'My Account' tab on your PayPal account; scroll down until you see the item for which you'd like to cancel the transaction. Click the 'Cancel' button underneath the 'Order Status/Actions' column. This must be done before the payment is claimed; once the payment has been withdrawn from your PayPal account or associated bank account, you won't be able to cancel the transaction and will have to ask for a direct refund.
Requesting a Refund
Once a transaction has gone through -- whether it's an original transaction or a refund -- you won't be able to cancel it. Instead, you'll have to ask for your own refund to recoup your money. Again, start by clicking the 'History' tab under the 'My Account' tab on your PayPal account. Scroll through your list of transactions until you find the one you want and click the 'Details' button adjacent to it. Here you'll see information regarding the person from whom you want a refund, including her email address; use this to contact the individual directly to request a refund. If you used a credit or debit card to pay for the refund you sent, it could take up to 30 days before the refunded amount is credited to your account.
Requesting Payment
You can also recoup your money by requesting a new payment. This is a separate transaction and will not be linked to the original transaction or the subsequent refund. Click on the 'Request Money' tab at the top of your PayPal account. Then click on the 'Request Money' button at the top of the next page. Enter the recipient's email address and the amount of money you're owed. Check the box for either goods or services, depending on the transaction. For a more formal option, you can also submit an invoice by clicking on the 'Create an invoice' button at the top of the 'Request Money' tab. Fill out the form with information regarding the transaction, including the recipient's email address, information about the item or service purchased and a due date for the payment.
File a Dispute
If you are unable to recoup your refund by requesting a new refund or payment, you can file a dispute with PayPal's Resolution Center. You have 45 days from the date of the original transaction to file your dispute. The Resolution Center puts you in direct contact with the person to whom the original refund was issued; if you're unable to negotiate a solution, the Resolution Center may be able to get you your money back.