Ford Tygervalley Bad Service. Wheels came off after service

I am extremely disappointed in the service that I have received from Ford Tygervalley. I had my Ranger in for it's 80 000km service, as that very evening we were driving through to Caledon. Whilst driving one of my back wheels came off... A manager at peugeot happened to see how my wheel was coming loose and stopped to pick up all my wheel nuts in the road. He had helped me and noted that the other three wheels were loose aswell. This resulted in major damage to the one wheel that actually came off. I have not been able to check the other wheels, I had requested that the branch have this checked for me. My vehicle went in on Tuesday and they only checked the one that had noticeable damage to it. They refuse to check the other 3 and want to blame this on the fact that these are not tbe original mag wheels that the vehicle comes out with and that it is wear and tear. This could have resulted in a fatal accident. I am disgusted in the response I have received from the service manager and have received no apology for the inconvenience caused. I urge people to please be vigilant when having their vehicles serviced at this branch. Sales department is great but their service department needs some improvement.