I never had numbness with the Giant Defy 2012(1) saddle, but it wasn't comfortable. I gave it a week before going back to the LBS--had there been numbness, I would've returned immediately. I finally went for a Specialized Avatar saddle which has worked well for me.
I am SOOOOO glad you got it fixed and, as has already been stated, another post showing what a good LBS does and why they need to be valued and supported.