The anti-bark training collars deliver a nasty shock, if they ignore the warning beep. The ultrasonic gadgets for pest control, mosquito repellers, and most anything else are pretty much a scam and basically useless. It's big business because they are cheap to produce, and consumers are quick to buy technical miracle devices. At such a low price, most won't waste more money and time, to return the product. None promise to be 100% effective, so it's not fraud.
Ultrasonic whistles can be used, if you train the dog to respond to it, but it's no diffrent than training to your voice, snapping your fingers, clapping your hands, ect... Might be some benefit in the field.
For your problem with the breeders, doubtful you get any better results than you did talking with them. Most of the breeders I've met, aren't the greatest class of people. They keep the doge confined in small cages, separated from the other dogs. They are very social animals, and need to interact. They give the dogs the very minimal of care and contact. Really bugged me, how they view the dogs as only a product. I'm sure not all are like this, but got a hunch many are, just too consistent with the few I've been around.