What does confirmed mean here?
A confirmed payment is included in a block. More blocks added after it make changing that part of the history harder. That is why recipients can wait for further confirmations rather than treating a newly seen payment as final.
A payment still waiting for a block is different. Do not assume that seeing a pending entry makes it settled, or that every waiting payment offers the same options. This page does not promise a way to cancel it.
What would a refund look like?
Imagine you send bitcoin to someone for a repair and they agree to refund it. They create a separate payment back to an address you provide. The original payment stays in the history.
If you send to the wrong recipient, there is no central Bitcoin help desk that can force that person to return it. A service may have its own support process, but that does not give it the ability to erase a confirmed network payment.
What should you check before approving?
Read the destination, asset, network, amount and fee before approval. Confirm payment details through a route you trust if something has changed unexpectedly. Care at this stage matters because a later request for help is not a guaranteed recovery route.