Bad experience at Mitsubishi dealer

[SUVshopper]

I dropped in today with my 1991 Magna to check out the 380 variants (the GT was a real beaut). I wasn't there for the sausage sizzle or the jumping castle.
I asked the sales rep whether it was possible for him to value my car, noticing it was a busy day for them. He acknowledged that they were busy but would still be able to value my car. Then he introduced me to a person who could value cars.
So I walked with that person to my car and told him the model of my car. However, when we were about 15m from my car, he stopped and didn't want to proceed further. He said that it had been a couple of years ago that he had last valued that model and he has to ring around to get a price. When I asked him to give me an indicative estimate (that's all I want) he refused to do so. And as he turned his back on me, he said sarcastically - $10,000 !
I was really upset when I walked back to my car. Anyway, I found out later that the person who did not value my car is one of the owners of that dealership and he has in the past also refused to value cars for other customers.
I've owned the Magna for 8 years and I thought of trading it in for the 380. Although it has only done 135K as it's a "second" car, I knew that I would be lucky to get a few grand for it. However, in the manner that I was treated today, I might just forget about any Mitsubishi !