Bad frame quality

I've been going to Specsavers all my life and the past 6 years have been problematic. Receiving spectacles and before a year the arms of the frame broke. Before it was repaired now I'm told of a 80% copayment. Which I paid. Not even three months and the replaced frames arm also breaks. Now I'm told of 50% copayment. Why is the warranty even in place? Also the two previous spectacles frame broke in the same place or part. I'm using one which was red but has brown arms. The previous flame from two years ago was white. Same problem. The quality is completely whack!