Budget Location de Voitures Nice Aéroport

This two star rating is for poor attitudes.
I had requested the BMW X1 and was given a Mercedes C Class sedan. We additionally requested and paid for a GPS system (12 euros/​day for 4 days). The Mercedes we received over the BMW we’d requested was understandable, as they were in the same level of rental car. Unfortunately, the Mercedes was simply going to be too small for our party which was comprised of five adults and five pieces of checked-​in luggage. We went back to the counter and asked for the X1, which we managed to get.
When we got to our new car, Tom Tom GPS in hand, we realized the BMW X1 had a built in system and therefore left the Tom Tom superfluous. So, I went back to the counter and asked to return the Tom Tom in hopes of getting back the 48 euros we’re already paid for the portable system. The employee was one I had hadn’t worked with previously and she was downright rude when she took back the system – ignoring us halfway through the transaction to discuss something totally irrelevant with her other colleagues behind the counter. Then, she refused to refund the 48 euros we had paid, stating that since we had use of a GPS system (the one BUILT-​IN TO THE CAR), we had to pay the 12 euros a day for it.
We didn’t understand why we were being charged as the Mercedes and the BMW were in the same rental class level and we had pre-​paid the same amount, why we had to also pay the additional 48 euros simply because the BMW had a built-​in navigator. And actually, I had requested the BMW X1 in the first place and I had been charged for it, which ought to have included the navigation system that was built in.
It wasn’t our mistake that we ended up with TWO GPS systems. It was Budget’s fault. And there was absolutely no need, when explaining the reasoning why they we keeping our 48 euros, to be as patronizing and dismissive as they were. She had the audacity to point at the website for Budget/​Avis France and tell us to lodge our complaints there. Which we will.
I’m not complaining due to the misunderstanding about the GPS systems. At the end of the day, I’ll pay additionally for the GPS system, sure, even if it already came with the car. But, I am extremely unhappy about the way my father and I were treated at the counter by those who were supposed to be offering customer service to paying customers trying to navigate a foreign country.
I would give one star, if not for the very helpful garage guy who helped pack our luggage in the car and pointed out the error of us having two navigation systems in the first place.