Unsatisfied customer

I'm very unsatisfied about the service I got at fishers. I brought a brand new ring in to be made smaller. I asked the consultant Claire can the ring be made smaller she looked at it and said yes. When I got the ring had it on not even 3hours started bending I took it back they said it would do that because of the shank that's thin. So I should walk around with a ring that will bend... The consultant was to tell me what would happen if I made it smaller and if I agreed to having it made smaller now the job is done they not taking no responsibility for their poor workmanship and lack of communication. They told me to take the ring t back to where I bought it that was perfectly fine before I gave the ring in to them it looks so bad and which will break anytime . They won't even fix the shank they say I should pay for it. I'm not happy at all with their service