Yes I agree withe RSK, tell him you want your car back, plus the trade in money and clutch money. See how quickly he drops the subject.
I traded in an escort a few years ago for a focus, the deal did not include the alloys on my escort and that was stated at the time, put when it came to payment the dealer was very angry that I had removed the alloys and wanted more cash. I told him he could keep the focus and he soon backtracked. Havent been back since and that was an official ford dealer
Chancers