Agree with folkfreak. Immediately offer a full refund upon return of item. Yes, probably best to offer return shipping cost too. Don’t get into a complex discussion or a war of words. There’s no "make him happy" endgame for such an unreasonable and aggressive person; offering up the reset button will buy you back your sanity as quickly as possible, and shows you to be an honest seller. Try to avoid a long slog with Paypal and/or Audiogon reconciliation. Most likely the guy got buyer’s remorse and is throwing a toddler tantrum to get his way. Fine - just end it ASAP, and put him on your very own black list for next time!
Hope you can soon get back to enjoying this hobby. Sorry for your troubles!
Hope you can soon get back to enjoying this hobby. Sorry for your troubles!