VSP Insurance review: They will not continue to repair lenses that crack - I bought these glasses over 1 yr ago.

I purchased glasses over a year ago and the right lense keeps getting hair line fractures/cracks at the edge of the lense. The eye/vision store repair the 1st 2, then the insurance co. VSP wanted to have them shipped to them to repair them the 3rd & 4th time. This time they tell me it has been over a year and will not replace the 1 lense for free anymore. Just to be clear, these glasses for different reasons (mostly lense) have been back for repair at least 6 - 7 times. The main problem I have, that I need help on is: Can the insurance company stop fixing my lenses if they are cracked. I am not a specialist and I do not know if this is poor workmanship or poor quality bicarbonate lense material. There were 2 times I sent them back due to poor workmanship.

Thanks
Lydia