I do all my BD shopping at Amazon. I've never had one problem since they started selling BDs. As a matter of fact. 3 months ago I accidently bought a BD that I already had. It was only a $10 one, but they told me to keep it and gave me back my money.
I haven't bought from a retailer in years, everything is at Amazon, TCM, WB, VCI, Screen Archives, etc.