We installed a new microwave/wall oven and the person installing it wired it incorrectly at first. He tested it by turning on the microwave...this caused a burning smell coming from it and a pop and it turned off immediately. He then re-wired it correctly and now the microwave doesn't turn on at all. The keypad for the microwave doesn't work either. The oven is the only part that works along with its keypad.

Is there anyway that the microwave can be fixed or is it a waste of time and money?

Thanks in advance!