While I am certain this incident was scary your house didn't burn down and your child wasn't hurt. I'd be upset too. However, now what you have is a broken dishwasher. Unplug it and wait for the repair person.

Just because your child was near the machine when it broke doesn't mean this is a crisis worthy of disrupting the entire repair schedule for you. It's still just a broken dishwasher. What MAY have happened really is irrelevent at this point.

Threatening lawsuits for something that didn't happen does not add to your letter in any substantial way. In fact, it probably lessens your credibility and adds unnecessary drama to your letter.

Also, on a side note, just because someone is able to look at a situation realistically and without undue emotion doesn't automatically make them childless. That whole "you must not have children or you'd understand" stuff just means that the parent is too emotional to see things in a rational manner. Believe it or not, some people with children CAN actually take a calm, common sense approach to life.