Who remembers date of purchase?

Sorry to post what must be a fairly common complaint, but why in the world do I have to know the purchase date in order to get help on my 5-6 month old WiFi extender that I purchased at Best Buy? And while I'm complaining, let me mention that the serial number is NOT on the back or the bottom of the extender I have. The little picture on the interrogation page is not anything like what's on my device. It's in a little slide-out panel that only my young grandson could locate after I gave up. Yes, eventually I got registered, and I will probably be able to figure out how to configure the device all over again. We had a new ATT "mother box" installed today, so now I'm trying to get the extender to talk to the new box. It asks for a password, and the password for the new box won't work on the extender. I've finally downloaded the help files, after spending 45 minutes registering, so maybe tonight I can sit down and figure it out. Netgear makes great products, and (although I don't remember purchase dates!) I have used Netgear products for years. But this episode has really p'd me off. I shouldn't have to go through all this after already having the device in use for several months. And -- by the way -- I'm pretty darned sure I registered the device right after I bought it, as NG somehow knows my email address....