If they have, you'll need to dispute the payment or request a refund if they haven't claimed the money.

First log into your PayPal account at paypal dot com.

From the top click on the activity tab, you'll see all your recent transactions listed.

Find the transaction you want to cancel and then click cancel here.

A confirmation pop up window will appear.

Click on cancel payment to confirm the money will now appear in your PayPal account within a few days, yeah.