My Doctor Didn't Give Me a New Invisalign Last Time I Saw Him, but Melted the One I Already Had...

My orthodontist has always seemed a bit rude, clearly not caring about anyone in the office. And I don't blame him; it's mostly low-income families that go in there because basically the only insurance they take is the stuff the government gives out; there are constantly little kids hitting the assistants, etc. Anywho, since he did my braces when I was a kid, and a very poor job at that, I went back in to see him in February. I explained to him that the braces (which I had on for three years!) had done nothing, and that, despite having worn the retainer I was given after the braces were taken off for roughly three years more, my teeth were slowly but surely going back into the position they'd started out in. Fine, he says, I guess we'll do Invisalign for cheap. I was ok with this until the last time I came in, this past Thursday. Instead of having a new retainer for me, he busts out a lighter, heats up/burns the plastic, pushes the plastic inward, and shoves it into my face. It's still hot and burns me, and it tastes like ash. I bite him out of reflex because it literally did not fit over my teeth - my teeth literally would not go in because he'd made it too small! I apologize, saying that biting him was a reflex, and that he cannot push it into my mouth like that because it doesn't work. He pulls the lighter out again, heats the plastic up, and pushes it out some. It's tight, but it works. Sort of. Now, instead of looking normal, it is slightly warped, has a GIANT BLACK BURN MARK IN THE MIDDLE OF MY FRONT BOTTOM TEETH!!!, and has pushed my two central teeth on my mandible together (they're pushing together like tectonic plates do when forming mountains...). Is this an ok thing for him to do? He said I'd be getting three more trays for my bottom teeth, but instead he's just wanting to melt the one I have. This seems like he's just trying to be cheap to me. What should I do?