I am the seller.
It was a mistake. I offered the refund as an easy and quick way to satisfy an angry buyer. I have offered to send additional chips for the buyer to search through and find the one that suits him best. All I have heard from the buyer is how I am trying to screw him. I know that I have done thousands of transactions with people, and they have worked out well.
That is my piece of the story.
Regards,
John