Unprofessional staff and Tokai Service centre

I found a ****** plaster in my car after it was serviced at Tokai Kia and Renault branch. You can see the blood is still pink and fresh. I wish I could upload a picture. There was a nail clipping as well. My husband and I were sitting in the parking and saw my car leave the workshop thinking it might have gone for a test drive. When the car returned we saw two people in the car and shortly after i was phoned to say the car is just being washed then it will be ready for collection. When we spoke to the manager he was rude saying that both people left in the car because the mechanic heard a noise on the engine and there is no way that the ****** plaster belonged to his staff because none of them were injured. Why would I be adament it's not mine if I can easily be proven wrong with a DNA test? He promised to send the footage of both men leaving, still waiting. I'm no expert but should the noise not have been detected earlier and not shortly before its being washed. The car is a year old BTW and I've never heard a noise. Ever. Anyway. I removed everything from my car the night before and haven't had any blood drawn recently so it's impossible for it to be mine. All of this amongst a Pandemic. I am disappointed and absolutely disgusted. I've reported this to Kia South Africa as well as Renault South Africa. I have heard nothing back. I still have the ****** tissue. Is there a way I could report them to a body or organization that they report to? Please email me on ***. Thank you