The buyer still has the item you shipped so I wouldn't be in a rush to
help them out, the case is closed and they tried to cheat you. It's good
you prevented them from getting or keeping any refund money since they
lost the case, but they still got t...
I think your buyer handled the situation poorly by threatening and
spamming you with messages, but I don't understand why you say the only
reason you asked them to open a return was because that's how you were
told it works... you didn't do that in r...
If you are having a few problems with stolen packages your place may not
be considered safe for delivery and you may need to consider a postal
box or somewhere else. I don't know if this was shipped in the box with
the HP logo visible or not, but if ...