one of the tires is out of whack and is causing the car to pull to the side. If balancing and alignment were done, and rotating the tires caused the car to pull in the opposite direction, then the guilty suspects are the rim and the tire.
a few weeks ago, my friend had a new set of tires installed and it began pulling to the left. after alignment, balancing, and rotation, it pulled to the right. He wen back to the place he got the tires and it turned out the new tire was faulty. replacing it fixed the problem