If the website had OVERcharged by $160 and the buyer clicked ok, I have a hard time believing that Z1 would have ever done anything to refund the guy's 160 bucks.
To be clear, I like John@Z1 and I still try to show my support and shop at Z1 occasionally, but it's quite obvious to me that they still have major issues from the top down, relating to ethics and customer service/customer appreciation.