Birth Defect in Sphynx Kittens sold in Gauteng - No refund from Breeder

We bought a Sphynx kitten from Altha Ferreira from Spynxcove in Pretoria and we were done in badly. The kitten lived for just over 3 weeks. She refuses to refund us after she sold us a kitten with con******* pulmonic stenosis. This condition was diagnosed by a Professor in Veterinary Medicine. The conduct of this breeder is ********* and she should not sell unhealthy cats. She is also owner of www.edmundo.co.za; www.petsandthecity.co.za; www.petpalace.co.za.