Ring stones fell off - Terrible Service from Lerato at the North Gate Store

I purchased an engagement ring on behalf of my brother at North Gate Mall on Saturday the 25th of May. I was very excited about this particular purchase because He was going to propose to his girlfriend that evening. The celebration was short lived because some of the stones fell off the next day which was on a Sunday the 26th of May. Since I reside in Johannesburg I couldn't go and request an exchange that day so my brother went to the store on the 27th of May and he received a horrible service from Lerato with very very bad attitude and was not willing to assist him, the only option she gave him was for the ring to be booked for repairs which obviously this was a factory fault hence the stones fell of in only a few hours of being worn. My brother then refused for a repair option since it was never our fault and had to return home with the ring. I then contact the store and spoke with a lady by the of Pinky who identified herself as the Store Manager, she then did a follow up and advised that Lerato said the ring was scratched. when I got home I found out that the ring was in perfect shape, this is my 3rd if not 4th purchase at an American Swiss Store and my latest purchase was in January this year.my ring is still in an awesome condition and this is my 5th month so I am just very shocked that a ring I just bought this previous weekend already has been damaged as Lerato said! I was a very happy customer to shop at American Swiss until my recent horrible experience and i still haven't received any feedback about my complaint.