I have the same problem with Amazon. Probably it is not Amzon's fault. It looks like errors of WD hard drive labeling.
I bought this model:
2TB WD SATA II hard drive with 32MB Cash and 3 year warranty, Model WDBAAY0020HNC-NRSN.
Amazon sent me:
2TB WD SATA III hard drive with 64MB Cash and 2 year warranty, Model WD20EARX.
Although it looks better than my order, in reality the model WD20EARX has a very bad rate. For instance - look at newegg.com
BTW: UPS Code and S/N on the box label and on the hard drive are the same but model numbers are different and the label looks like a fake. I asked Amazon to replace HD but I am not sure if they have the model I bought.
As I wrote in my initial post, I asked Amazon to replace HD. A few days ago I received the same wrong model WD20EARX in the same right box WDBAAY0020HNC-NRSN. I send all detailed info to Amazon and believe they will do something. Sorry, I don't have time to fight with Amazon and/or WD.
After some online investigation I found that WD canceled the model WDBAAY0020HNC-NRSN aka WD20EADS (2TB WD SATA II with 32MB Cash and 3 year warranty), probably because they payed a lot of warranty money by reason of: their drives rarely worked for 3 years.
A few people write that the model WD20EARX can be used instead of the model WDBAAY0020HNC-NRSN, but it is not my case. SATA III WD20EARX model does not work with my SATA II controller. Any WD recommendations about speed decreasing and any jumper settings don't work too. I bough an eSATA enclosure which works with the model WD20EARX I received, and began to use HD with the enclosure. I hope it will work at least 2 years...