You mean they will not allow you additional time to train and retest?
That would be crazy for as much as they are charging.
If there are other people that you know who feel the same way, I would write out a list of areas in which you think they are lacking in to the degree that it would justify additional time training in.
Have a well written document, typed out. All of you sign it.
If needed to gain their cooperation i would let them know you are prepared to bring the issue to the awareness of the public.
If you seriously think this is a problem, then they know that these days, it is possible to connect with other past students that went to that training and together you guys might find a lawyer willing to take it on as a class action lawsuit.
Now keep in mind, my comments are based on what you have stated alone. I don't know the story. I know your version of it.