Cracked windscreen while car in their possession

Wish i could give them zero stars Their service up until the point of collecting my car wasn't bad, however, my car was returned to me with a massive crack in the wind screen (which obviously wasn't there when I left my car with them). I brought the manager on duty's attention to this immediately and he told me to contact their director, Alfred. It took three emails before Alfred even responded, and he tried to tell me that the crack must have been from a pre existing chip. I find this weird as a previous reviewer experienced the exact same issue. They deny any of this being their fault and instead of treating customers with care, will just ignore you. I would avoid using this company.