Hello. Thanks for writing in. Unfortunately, stress can really cause cats to "hold a grudge" for a long time. The things your breeder recommended are all good but they may take some time. I would try getting some Feliway from your local petstore. This is a synthetic cat pheromone that can relieve anxiety. If need be, you might have to resort to getting soem anti-anxiety medications from your vet and medicating her for a little while, until she can get over this. Please let me know if you have any other questions. Hope this helps.
Cat Veterinarian
7 years of clinical veterinary medicine and 17 years experience caring for household pets.