How to confirm paypal account for a partial refund?

[thegreatit]

Hi a seller sold me a headset that was supposed to work on both a PC and a PS3. It was $15, I was so excited but you do get what you pay for. Upon receiving it I found out that it was clearly made for a PC and while the audio and mic worked fine, the volume was painfully loud and the volume controls only worked on a PC.

I messaged the seller and informed them of the issue. They replied that they'd partially refund me $5, if I agreed to this I needed to 'confirm my paypal account'.... sorry if this is a stupid question but what exactly am I supposed to do? How do I confirm my paypal account... and is this necessary? I remember I was refunded once for an item that never showed up in the mail and I didn't have to confirm anything O.o