Turn Signal Switch problems of the 2003 Toyota Camry

I purchased a 2003 Toyota Camry and discovered what I think is a safety concern. The turn signal left or right does not shut off automaticly when exiting or entering a ramp or when taking a turn that does not requier a full turn of the steering wheel. My wife been in two altercations ,one of road rage from another driver and the other was a near accident all due to signal not shuting off automaticly when returning the steering wheel back from making a left or right turn . Never in the 26 years of my driving cars and trucks have I had vehicle that has done this and I feel this is a safety issue. I called Toyota headquarters about this problem and they said flat out that they do not owe me an explination . Its to bad I expected a more responsible reply from one of the world's best car manufacturers.