Well I dont like prong collars. Always trained mine with buckel collars, only wearing a show lead and choke for show.
Try the reverses method. Take your puller- when the dog starts to pull, reverses direction and call the dog too you but continue to walk the other way.. Walk along.. when the dog starts to pull, reverses direction. At first you wont feel like you are getting anywhere but they will learn if I pull I loose what I am pulling at..