I think I would change vets...I love getting my pups at 6 weeks, and have never had a problem, and actually have had less problems with biting etc. from the ones I've gotten at 6-7 weeks, but, I would never take a 4 week puppy..
I love the pee pads, and they're especially great for people who have dogs and can't be home with them to take them out..I'm home all the time, and I still use the pee pads, as that's what works best for me. good luck in whatever you decide to do.