glasses

Don't know if this is the right place but here goes. In April I bought my 14yr old designer glass from a well known retailer. After a few weeks the arm dropped off, the shop replaced the frames, nearly 2 weeks ago the same thing happened so I took them into the shop. I called in today and what they are saying is that the make of glasses is at fault, they're saying the quality of the glasses is known to be faulty, they are awaiting a phone call from the makers to say if they're going to replace the frames or give a refund, the shop won't do anything, they said that they've had problems with this make before ( should have told me that before I bought them) With anti scratch coating and insurance they cost me nearly £200
So where do I go from here? the shop are having a dispute with the makers and we're being caught in the middle.