Terrible service

I rented a vehicle in February and paid a deposit as is normally required. On returning the vehicle and returning home, I had not received the refunded deposit. I was information that there was damage to the vehicles windscreen. I requested further information on this as I advised that I did not experience any damage whilst using the vehicle. I was advised that an investigation was taking place but 6 months later and countless emails, I have no response and no refund.