
So where is this puppy now? Still with the person you left it with, or back with the breeder? I'm afraid I'd have wanted to take the puppy back to the breeder - way less trauma, for the puppy! That way you could have sorted out what would happen about a refund.
This is indeed a difficult situation - as a retired breeder, and this really only happened once in the few litters we bred, I'd make a refund after only 4 days, but probably less a minimal 'boarding fee' for the time I had the puppy back before it went off to a new home (unless the breeder decided to keep the puppy). To protect my reputation, I'd always make a refund, especially after only 4 days. At least the breeder, presumably, got the puppy back!!
ps So she's blaming you - why? We all make mistakes and at least she is, hopefully (!?) getting the puppy back. She may be waiting for you to return the paperwork?