I actually purchased 3 promos when I discovered the service (but before the issues with it came to light), so I have one running today as well. Likewise, I also received the message stating that the email would go out between 10am and noon. Thus, they get points for being responsive, if nothing else.
As to the effectiveness of the promo, I'm not convinced it did anything. I ran it on the first book in my Warden series, but that book is part of a Kindle Countdown this week (99 cents), so it was already in the public eye, so to speak. That said, it did get some page reads, but I'm attributing that to the fact that I plugged it in my newsletter yesterday, and it's probably picking up some love from the release of the audiobook for Book 3, which happened a few days ago. (As evidence of this, Book 3 is currently ranked about 3700 on Audible, while Book 1 and Book 2 enjoyed a nice rank improvement to about 17,000 and 13,000, respectively.)
My third promo runs next week, but it's on my scifi novel Terminus that was just part of a 99-cent BookBub deal this past Sunday, so - assuming there's a tail - I think it will be difficult to measure the promo's effectiveness.