Don't trust them. Only call or believe them if it is a very simple question.
I recently bought a Magic Mouse and jolly sexy it is too.
But I couldn't get it to connect. Download the new software update, yes. Turn off, turn on, turn around, touch your toes. Nothing worked.
After considerable time (3 hours) spent with Applecare on the phone and carrying out their instructions I was still no further than when I started.
Called a friend who came round with his macbook and connected with the mouse without difficulty.
So Applecare suggested a clean install of OSX. My mate thought that rather extreme and suggested I search the interweb and suggested a couple of Mac forums.
So, 5 minutes later I had removed the USBOverdrive.kext and installed my Magic Mouse!!!
Difference was that I had removed USBOverdrive but the kext remained. My mate also had UsbOverdrive installed so it was the leftover kext which was causing the failure to connect somehow.