One element on my Frigidaire cooktop would not turn off even with the knob turned to off. A repairman came and assessed it and said the switch was bad. A switch was ordered and he came back with it and put it in. He turned the burner on, it heated for a few seconds and he turned it off and told me it was fixed. I paid him and he left. I turned the element on, it began to heat and then there was a flash of light and a loud cracking sound and it turned off. He came back and told me that the burner element was bad and he couldn't have known that till he fixed the switch. My question is if the burner element was bad, how was it staying on continuously before he fixed the switch. Does this explanation seem reasonable or is what happened indicative of what would happen if a switch was put in incorrectly (i.e. backwards)? I want to be fair but if the burner worked before the new switch was put in, shouldn't it work now if the switch was installed correctly?