No response to enquiries a month after damage to vehicle

I took my car for a wash at this place abput a month ago and when I fetched it, noticed that one of the parking se sensors had been pushed straight through the bumper. I reported it immediately before I left and was promised that they would check the video surveillance and call me. They never called. I tried to contact them via email, facebook, whatsapp and went back to the car wash again but still the owner has not responded to me at all. I was told by the so-called supervisor on duty at the time that they saw nothing on the footage that insicated that they were responsible, yet they will not show me the footage. If there is nothing to hide, why not release the video footage and prove your innocence?