VW Strijdom park Missing belongings

I took my car for service to this dealer in December. Over the weekend I got a puncher only to find the lug wrench missing. I don't open the spare wheel side. I have alerted VW strijdom park about this, they advised that they never took anything nor open at the back servicing the car. I'm totally not happy with this as I am the sole driver of the car. The service manager and Dwayne advised me to buy a new spanner