Thursday afternoon I printed out a copy of the dog's dumb DNA report, took a new black Sharpie and scrawled "REALLY?!?" over several recent pictures of the dog, wrote a polite letter asking for either a do-over or my money back, and mailed a fat envelope to the company in Maryland that makes the dog DNA tests.
Just after noon today I got a phone message from someone who works at the company. She is sorry I was disappointed with the test and she will review the results; she just needs to ask me a few things first. I called back a few hours later and left a message for her. I'm hoping she'll call back tomorrow.
E-mail and web forms are useful for lodging complaints, but I suspect it gives you a slight edge in the customer service game if you go full-bore crazy and start printing shit out and affixing stamps to it. We'll see what happens next.