Gosh, so sorry you and the furbabies had to go through this. I'm furious just reading your post
As far as kennel cough goes, my vet once told me that when you give them a kennel cough shot it doean't mean that they won't catch it at all. It means if they happen to catch it at some point it will be a lot milder.
I would definitely walk in and demand to talk to the vet himself/herself. As far as the money goes, THEY are the ones that should be giving you a refund!!!!!
If I were you though, I would go get them checked by another vet at another clinic ASAP. You never know. Besides, another vet's opinion on their condition might come in handy once you go back to set things straight with the clinic that is responsible for their condition.
Good luck and please keep us posted.