Sounds like tire pull. One of the front tires is defective, probably the one one the side that it pulls toward. Swaping the tires side to dide is the definitive test for this. If it is a bad tire, the pull will follow the tire. Take the car back to the tire dealer and tell them what you have gone through. There should be no problem getting the tire replaced. You are far from the only person that has had this problem.
