That seems odd - I really don't see Z asking a customer to resend the wrong order to someone else?
I could be wrong - but there was a new guy who said the following while posting his concerns - he said this...
"I tried ordering 12 2ml vials of sus250 from his euro pharm and got 12 20ml vials of Z line"
Everyone was responding - Dude you just hit the jackpot - Z's going to be pissed - and some heads are going to roll in the shipping department!
Z's response was ... "it's ok - people make mistakes" - and so on...
Who knows - I might be wrong but I've always seen him over compensate the customer whenever there is an error.
Even when I had a qty error with an item - Z over delivered and I ended up getting 40% of my order for free.