Munku, my impression of the MX500 is that it is top of the line. I would think that there would have been a warrenty. Any way you can put it back together and send it back? I have had some good experiences with them and think they might err on the side of the customer.
One thing that is preventing me from buying the MX duo (with the keyboard) is that I saw a neato Micro$oft mouse the other day that had SIDE scroll. That was nifty. You tilted the wheel to make it scroll windows to the sides. I was kinda hoping I would see Logitech follow suit since I like to buy their stuff (and we don't need one computer company to rule them all), but I bet MS put it in their OS and then patented it so only they would sell mice that take advantage of the feature.
Buy.com has it here:
http://www.buy.com/retail/product.as...951&dcaid=1688