With your ability to analyze things and express yourself clearly, and you 3 negative experiences, are you willing to call the company and ask to talk to one of their product engineers? They may appreciate learning what you have experienced. Otherwise, I fear customer service probably just throws them in a box, and nobody has gone back to the source and explained the exact issue.
I would hate to have the company to just decide to take the product off the market due to "excessive failure rate" - it happens way too often in manufacturing.