Do you think maybe you are getting old eggs? I sell eggs, but I keep myself to extremely high standards. I never ever will sell eggs that are over 7 days old and those are kept in a special fridge we have set up to hold a constant temp of 50 degrees. Most of the time the problems with hatch start out with the way they are stored prior to being shipped. Make sure your eggs you buy mail order are from a reliable source.
I am so sorry you had such bad luck.
I am so sorry you had such bad luck.