Lenskart — New Half frame lens pop up easily

My Brand new Half frame spectacles' lense just pop up due to loosening . I have not expected that a huge company like lenskart will give low quality products. I think that I would have bought it from a local store nearby . It will not give such a defective frame
The lenses are so expensive if it continues to fall again and again it will get damaged.
Then the worker at the showroom started giving excuses that in half frames this problem is common. Also told us for insurance .
When we bought it no one there even told us about the insurance and this problem of half frames.
They just feel selling is the most important .