While baking a pizza in the oven, the broiler elements came on and burnt the pizza and nearly started a fire. After turning the switch to the off position and removing the pizza, I noticed that the broiler elements did not turn off. I turned the power off at the breaker box to cool the oven. Next, I turned the breaker on and observed the broiler elements heated again even though the oven switch remained off. I have the breaker to the oven turned off until I can resolve this.