Dislodged diamonds

On my birthday in April of this year, I noticed a diamond missing out of my ring. I searched everywhere for it but was not successful in finding it. I couldn't understand why or how a diamond could fall out of a ring from such a high end jeweler. I took the ring in and they said they would sent it away to be assessed/ serviced, and replace the diamond at a fee. I received my ring back after a week or so. Six months later it happens again. I am not sure if it is the same diamond or a different diamond cause of the style of the ring. Now i am told that they "understand" it was not my intention to dislodge the diamond but due to the everyday wear of the ring this is bound to happen, and could be from a knock. I have been so cautious since having it fixed, and what are they implying, that in order for your jewelry to remain in a good condition you cannot wear it everyday? When it happened the first time I was understanding, but how can the same thing happen so soon again. I refuse to pay for the same repair. What if i have it fixed and then another six months down the line it happens again? With all that repairs i could just buy another ring. And to my surprise I came onto Hellopeter to find the same complaint from another customer. Wow, so much for fine jewelry.