Extremely Poor Customer Service - Refusal to replace broken windscreen

Last Thursday I took my Renault Clio in for a service, the car was checked over by the Service Adviser as per usual and all marks etc. were noted. It was noted that there were 2 small stone chips in the windscreen and i was asked if I would like for them to repair the chips. Later on that afternoon i received a call from Renault Silver Lakes to say that they will not be fixing the chips as the windscreen is cracked. The windscreen was not cracked when i left it there in the morning. I was then told that it must have cracked when they started washing the car. I opened a complaint and was told that the Service Manager would call me. I only received a call on Monday this week during which the Service Manager informed me that he does not have the authority to approve the replacement of the windscreen and that he would need to discuss ti with his Dealer Principal. Today I received another call from the Service Manager to inform me that the Dealer Principal felt is is not their responsibility to replace the windscreen even though it broke whilst under their supervision. Who prey tell is responsible then? Extremely poor Customer Service, i will definitely not be going back #Furious