If the pet shop owner said they did vaccination on the pup, they should have the vaccination card as prove and should be given to your friend to follow up with any future vaccination requirements. The pet store can't even provide the vaccination card, it is kind of obvious that they just crap out the story just so your friend will buy it confidently.

Do what's best to fight. Cause if we as consumer do not stand for our rights, more pet shop owners will neglect these issues and who knows, more innocent animals will die!

It makes me feel so angry to hear such pet shop owners are so irresponsible to these details and tried to avoid refund.