Wrong Product Model on wdc warranty check

Hi everyone, I have a wd passport essential, on the back was writed: WDBACY5000ABK-00. But when I check it’s S/N on website ( http://websupport.wdc.com/warranty/serialinput.asp?custtype=end&requesttype=warranty〈=en), it gave me Product Model is WDBACY5000ABK-PESN. So i confused what is my WD’s P/N? WDBACY5000ABK-00 or WDBACY5000ABK-PESN? Someone please explain this to me. Thank you

Only the first part before the dash is the one that matters, so don’t worry about it. 

They are so messed up.  I thought it was only one series.  Here is proof that there are more problems.

In March, I sent in a WD30EXRX for RMA replacement.  This is an internal drive.  What was returned was a My Book External 3TB assembly.  I guess I should have just kept it and sold it on eBay because it is now almost June and I don’t have the correct drive.  Or ANY drive!  I returned the wrong one (at least they paid the return postage) but they are not in any rush to get me the correct drive.

Key in the serial number of almost any of the WD30EZRX drives on eBay and the system will return a MyBook Essential 3TB product number.

What they have done is to use the same serial number series for two different product.  And apparently they have done it twice.  And they are putting the pressure on ME to prove that they are screwed up.

Thanks?  FIX YOU SYSTEM!!!  You have really complex and cryptic serial numbers and a very large space to fill them into

.  There is no reason except stupidity to reuse two of these series of numbers.