I noticed today that my mounting tabs on left side of air dam are broken on 2009 Toyota Camry

I had a service a few weeks ago at dealer and today I noticed the mounting tabs on left side of air dam are broken, I drove to Broadway Toyota in Portland, my car has a platinum warranty but was told this was not covered. I should have guessed. I have no visible damage or reason as to how or why this broke. It may have been from mechanic at Broadway rotating tires-maybe he broke them somehow and never told me. Anyway they refuse to pay for repair and they want $764.00 to repair and paint. Has anyone else had this happen with their 2009 Camry. I think it must be defective if the mechanic did not cause the damage.

Asked by for the 2009 Toyota Camry