Petshops cannot be trusted. That's why it is always advisable to get from a reputable breeder. In Malaysia, petshops mostly get their puppies from puppy mills and the puppies are always sick during sales or they carry some sort of virus. My point is, petshops only want to sell so they will tell you all sorts of stories just to make a sale. My friend bought a maltese that cost him RM2.5k and he was shock to find out that it has Tick Bourne Fever, a disease that can spread to humans. Luckily he had black and white contract with the petshop so he was able to do something about it and get a refund.

Best is if you don't trust a petshop, come up with your own contract. It may be troublesome but it can help you a lot in the future. Still, the best place to get puppies is from a good breeder.

Like what Silvanus, this case is not solid. If you have proof of a cert then you can argue your case.