Meggi, you're auto disaster had little to do with the dealer. You blindly attended a Madza dealer and bought a 2002 Cherokee for $7000. Even without knowing the mileage, that is a $3000. vehicle. On top of that, the 2002 Cherokee was the worst Cherokee Chyrsler ever made and they're all crap to start with. You did absolutely no prior research into that year/series Cherokee or you would have never considered it. They are JUNK.
Used cars on used car lots under 10K are other ppl's discarded junk. So you attended this lot, bought blind, and signed a contract. How is this the dealer's fault

The dealer has made $2500 net, the salesman's made $500., of course they are going to hold you to it. You could have run out the door and lost you're $1K for being a fool.
Scarborough Mazda is no different than any other GTA dealer. They are not part of the public service. Their time and "advice" is not FREE.
The lesson here is that you did everything WRONG. I'm not totally clear on what trim level you bought, but this time next year your vehicle will be worth $20K providing no change in gas prices.
I would seek out an accountant to review you're finance agreement because based on your actions thus far you could be paying a huge interest rate premium.
If you have not received the vehicle as of yet, walk away.