Vehicle used for joy ride

I was very upset when I collected my vehicle from Car Service City Menlyn, after booking it for a minor service and I saw my petrol light was showing I need to refill. I handed my car in with the petrol gage showing it was just under a quarter tank petrol in my car. Shocked I went to the front desk, but like always there was no one to assist me. I entered the workshop and found a guy sitting at a desk and told him to explain to me how was that possible that my car shows my petrol on empty.

He quickly jumped up, went to the reception to collect my paperwork and then realised that there was something like 45km, if I remember correctly, could be more, added to my car speedometer. I was just in complete shock. He told me they will reimburse me an R100 for the petrol and also confirmed that there test route should only be 6km...

So my question is........ Why the extra km, who drove my car, where did they drive it to, what did they do with it, and how did they drive my car that it used almost a quarter tank of petrol...!!???

I am so angry that they violated my trust as a client and used my car for a "joy ride" and just popped R100 into my hand and said sorry and send me on my way...