I had an upsetting experience at this Mazda dealer...

I had an upsetting experience at this Mazda dealership yesterday.
I had booked my car for a service on the 31st of December and had discussed with the representative adding Android Auto to the car, at no charge, considering it now standard across your range. However, when I arrived to collect my vehicle the service person wanted to charge me $500 which was not a charge I agreed too, I was humiliated and confused. The service person refused to give my car back which has been extremely stressful and inconvenient.
From the sale to the servicing owning my Mazda has been a disappointment.