My car left on a parking lot

My car was left on a parking lot after a service and I was suppose to collect it after working hours. Guess what the lady left without contacting me and the keys were left inside the workshop. It was so sad that I drove all the way from work to collect the car only to see it on a parking lot and I was told that she never left the keys with anyone even securities. The initial agreement was that she will leave the keys with one of the security so it can be easy for me to just collect it, I dont understand why people are doing this after paying so much installment!!!!