Pet Stores & Breeders

We purchased a German Shepard from a Pet Store and had all the papers and the Breeder's information. When we brought her home she had diarrhea. I called the pet store and they said it was the change in food or just a sensitivity to the change in her environment. We ending up rushing her to a vet when she started vomiting. We had only had her for 3 days. They checked her for all kinds of things and put her on a special diet. She straightened out in a couple of days and then it started again after a month, so she has had bouts of diarrhea on and off. We've now been to 2 different vets. She has all her shots. Before her lyme shot she was a healthy and 60 lbs. She started the next day with diarrhea, and in two weeks was down to 50 lbs. We of course went to a third vet to get a second opinion. They found that she has a pancreas problem and can't digest her food. From start to finish with the vets, we have spent over $3,000 in vets, tests, food, and the most recent vet bill was $625. We are a retired couple on a fixed income. I called the Pet Store and the Breeder. The breeder offered to give us a replacement. We don't want a replacement. We want our dog. She will be okay as long as she stays on special food and meds at the price of $650 a month. I called the Pet store to see if they could do something. We ran out of money and had to return her to the Pet store and are trying to work out a solution with assistance with the meds and food. Isn't there a law that prohibits this kind of stuff? What can I do?

I bought a cat a month ago from a breeder. The breeder said the cat was healthy, but after a month I took him to the vet for the shots and the doctor said he has a testicle problem and needs surgery.