iPad ****** from Car and Poor Service

I rented a vehicle from Hertz on the 26th March, when we received the vehicle we were given a car that someone else had just rejected because the aircon was not working, we were then given a replacement car which had not been cleaned properly and I noted this on the rental slip. We returned the vehicle on Tuesday 31st March and after about 20min having returned the car I realised that I had left my ipad next to seat in the car. I immediately called the rental office which then put me through to the car yard and I informed them that I had forgotten my iPad can they please keep it for, After waiting for them to call me back I called again that same day and they said they would check and get back to me. The following morning I called again and asked for the manager who promised to revert to me but no response was forthcoming. I was promised that they would review the security cameras and since then i have had no response. Someone took that iPad from the rental car and Hertz has made no effort to assist me in this regard.