This happened several times. Needless to say they were upset at the time they had to spend trying to get the problem fixed and still no resolution. They of course came to me, their salesman, and here's what I told them to do. The rules vary somewhat by state but generally read that after a certain number of repeat visits for the same problem, whether it's been replicated or not, a customer has some recourse. The procedure is usually a long hard haul, but you'll get there.
Every manufacturer has a customer service department.
The contact number will be in your owners manual, probably in the back. Call the number. Keep documentation of your service visits so you can prove your case. The manufacturer will send a representative to the dealership regularly to deal with service and warranty problems. An appointment will be made for you to come in and see this person and have them look at your vehicle.