Ehh, this brings back bad shameful memories. I worked sales at a new/used dealership, but ended up getting fired

I thought I could sell doing things "the right way". When I wouldn't play to the sales manager tune of "try to get $1500 more out of them"..."change this"..."raise that"....
Anyhow, I'm ashamed I ever tried that. But I'm glad my standards didn't let me pull that junk. I dreaded work, but I wasn't going to quit. I didn't want to pull fast ones on people, drop low credit scores into a 20% interest loan on a car that wasn't worth the down payment... needless to say, I shut down, my sales dropped, turned over my customers, and left with my desk plant after the sales manager said "Can I see you in my office".
I'm ashamed to say I sold cars. I'm embarassed that I got fired. Pissed that I look like a failure. And glad that I wasn't anything like those snakes and was 'out'.
Anyhow, sorry to hear they pulled that on you. You did right by walking out and refusing what they tried. You should find a bike somewhere else, then ride up to the dealership, ask to see your sales manager and the owner, show them the bike, tell them what you paid, and thanks for making you go elsewhere. Then get on and drive off.
Really though, most owners, sales managers, and finance snakes don't really care in the grand scheme of things. They're the type where they'll say, "ehh F that guy" and go on doing the same things. That's their way and they'll never change. So, just leave them long gone and don't look back.