The owner (and sole member of staff) is taking some time off due to illness, which was only recently diagnosed. There was a post about it last year, either here or on ML. I'm therefore not surprised that emails are not being responded to. I have no reason to believe that there is any reason other than this behind the lack of response but it would admittedly be helpful if he were using an out of office message so that emails at least received some response but he may have overlooked that in the circumstances.

While this doesn't help your financial position, I hope that PayPal sorts out your refund.