Very bad service

I bought an engagement ring at American Swiss Bronkhorstpruit and within 2 weeks one diamond fell out and i had to take it back so they can fix or exchange but they refused saying it was not taken good care of left me wondering if the ring is not suppose to be on the finger the whole time.. And they did not consider the Guarantee of the good they sold to me.. They need me to pay 2/3 of the total cost the ring inorder to replace the diamonda that was lost imagine how awkward is that. Tasniem Dada manager from Eastrand she was useless and Rose from bronkhorspruit bad service