I have been going through a similar situation with a petstore near me since 2004! We just moved into our new house and were looking for a lab puppy. We ended up at a local pet store just to look... and they had 2 black great dane puppies wandering around the store. They were both very ill. Pnemonia,kennel cough,coccidia,round worms,hookworms...you name it they had it! I ended up buying them just so I could get them to a vet. When I brought them to my vet the vet said he would try as hard as he could, but didn't think they would make it through the night. They did eventually get better but were hosptilized for 3 months.
Just because kennel cough may be "common" in puppies does not mean that it is not animal abuse if left untreated. It will turn into pnemonia.
I would call the police dept. if I were you. Request an officer to be sent out. They can require the pup be seen by a vet within so many days.
Good luck
