I wish you luck with Paypal. In my experience they will only cover you if you were sent something other than what you ordered, or never received anything. If the product was delivered and defective, they adopt the "not our problem" attitude and tell you that you have to work it out with Bob.
Since then, I seldom use Paypal, and will use a credit card - after doing my research to make sure the company I'm sending payment info to is legit.