********** sale of Apple products

Purchased an iPhone 6 Plus from I store The Glen a year ago. The screen has come loose from the phone and when booking it into I store for repairs I was informed that the display is not an original Apple display so they will not repair it or even quote on it. I have comprehensive insurance on this product from the day it was purchased so why would I pay for a 3rd Party to replace the screen when I can just claim for an original screen from my insurance. I have complained on 2 previous occasions to the Core Group about The store at the Glen reselling faulty products but there has never been anything done about it. The Core Group is refurbishing products with unoriginal parts and selling these to customers as original Apple products.