They broke my frame!

Harveydos

I sent my rimless glasses of to be re-glazed to Glasses Frames and Lenses.com and as they offered all the warranties and guarantees on their website I trusted them to provide a good service. I had managed to break the right side lens and the sent the glasses as they were with the left arm side still attached to the left unbroken lens and the right arm with the broken lens.
The frames came back fitted with the new lenses and to my shock they were covered in dirty fingerprints and smears and the left arm was not attached to the left lens. I assumed that during the removal of the left lens the technician had managed to break the head of the screw that attaches the lens to the left arm and left the broken thread part in the frame and that piece obviously unattached. When I complained they stated that the frame was already broken before the glazing proceeded and that they had called me to explain the situation. During that brief conversation never once did she explain that the screw had broke and was now lodged in the frame rendering the expensive Oakley frame unusable, she stated that they just couldn't get a screw in to the hole so I did give the go ahead to proceed the with the lens manufacture and I would be prepared in getting the screws fitted locally.
When I received the frame back and saw what the actual problem was and after taking the frames to local opticians and to a jewellery repair shop who both stated that it could not be repaired I contacted glassesframesandlenses.com by email and they will not budge claiming the damage was already there before they commenced work. A total lie as the left frame arm was attacked to the lens when I posted the glasses to them. What can i do, if anything...??