It’s not possible to cancel a completed payment from your PayPal account.
Contacting the seller is often the best way to solve a problem. You can find their contact details by going to your Activity and selecting the payment. They may be able to issue a refund or help with a return.
Otherwise, you can open a dispute within 180 days of the payment date. Here’s how:
In a dispute, you can exchange messages with the seller in your Resolution Center to try to solve the problem. If you’re unable to settle the dispute, you can escalate it to a claim. By escalating it to a claim, you’re asking PayPal to investigate and decide the outcome. A dispute will automatically close after 20 days unless it’s been escalated.
You can check the progress of a dispute or claim at any time in your Resolution Center.