maarco & associates they stole items from my vehicle. they are a valet service in hollywood woodland hills, California

I used Maarco & Associates for valet service at Greystone Manor in Hollywood.  They stole items from my vehicle.  When I asked for reimbursement Maarco & Associates said they are not responsible for stolen items.  I feel I should be able to trust a professional company and their judgment on who they hire.  I have a nice vehicle and items inside it.  I will never utilize their services again and now have concerns with using other valet companies due to their unprofessional acts.