Poor ring quality

My Husband and I bought a ring from this shop last year in January, it went for resizing and I only started wearing it in March last year, by August last year one of the stones fell off,The ring was changing color so we took it to Arthur Kaplan gateway after 2 weeks I was phoned and given a quotation of an amount to fix it which we refused and we were told to come and collect the ring as there no warranty for them and the reason the stone fell odd is that I had bumped the ring or something. I took my ring back and now three stones fell out again February not even a year of wearing it I have 4 stones missing from my ring.

I am sad and angry because we spent a lot on this ring for me to hide the holes with my thumb so that people don't see the joke of a ring I'm wearing, I dont want this ring anymore, how do i get this issue resolved because I feel like I have worn even a quarter of the amount we spent