This seems to be a matter for a small claims action. Be sure to document everything, particularly the call in January.

Ask the "medical director" to cite the statute or regulation their limit is based upon.

Moving to debt collection, so you get better answers.

Asked and answered - once is sufficient.

How soon after purchase did you take the puppy to your vet for a proper inspection? What, if any, documentation do you have for this purchase? ...

This is a sad, and unfortunate, occurrence. How long did you wait after buying the puppy to take it to your vet? Does your state have a puppy...

NOT your issue, and advertising it on an open site does not help your cousin. He or his parents can deal with this.

Your damages are vet costs and the charge for the negligent grooming. If the groomer will not make good, your remedy is small claims court.

Moving to family, which is the relevant practice area. Discuss this with a trusted adult, preferably a family member, such as a grandparent....

The best you can do is follow attorney Koslyn's excellent advice, and hope that you can actually recover either the dog or damages from the other...