They are attempting to extort a member. That’s BS. Will not order from QSC again.
It's a cultural difference.
In the US if something is sent to you which you didn't order, by law you are under no obligation to send it back.
A vendor may ask, and often sweeten the deal in order to incentivize its return. And some people may return it out of their own personal ethics. But if you don't there's no obligation and a company may not "punish" you by keeping your money from a later order.
In Asia and Europe. the police would likely be at your door for failing to return or pay for the unordered goods.
So now both parties are outraged at the behavior of the other.
If the goods were indeed worth $1000 QSC would've been better off offering a $200 credit to minimize the cost of their error and compensate the recipient for the trouble of taking time to send it onwards. The grey legal area of the goods might be too much for the recipient to be willing to deal with, and QSC should understand that and chalk it up as a loss as they would any other shipment that's gone missing in transit.
Neither party was in the wrong here, but keeping money sent in good faith for a later order is not acceptable by American standards and he should be refunded, or better yet just continue doing business as there's truly nothing to gain by trying to penalize the customer.
It's really in QSCs best interest to resolve this quickly and put it behind them. Again, this could've just as easily been a seized package or lost in transit. It's a business expense, only this time an error on QSCs part and not bad luck.