I'm having a frustrating time with my bath faucet in trying to adjust the water temperature. I turn on the hot water and then cold and it's just right but in a few seconds there is nothing but cold. The hot water is turning itself off. I can turn it up and the water's too hot. Adding more cold ends up making it all just cold water. What the heck is going on and does anyone know what I can do. The faucet handles are about 2 years old.