I am having two problems with this stove/range, model #KERS505XSS03

1. The light will not turn off. It went on when the doors were opened and now will not turn off. Eventually, it turns off on its own.

2. When trying to bake something at 500 degrees, the oven dropped the temperature to be set at 290 or 295 (I can't remember). I tried setting the oven at 400 and the same thing happened, both the top and bottom, and at all settings (bake, roast, convection).