bro Clubber108, you're so cool with the girls according to your stories in sbf and yet so blur with your biggest liability. Haiz....
If you've already got the car and signed your life away, go sweet talk the salesman to give you clear answers. It is likely that COE is in the financing package. As for the rebate cheque, you have to read the fine prints, but by now, you would most probably already lost it. But you can insist the salesman show you the sucker clause before you even consider passing it back. I would bank in the money into your own account first and act blur with the agent until his lawyer's letter of demand comes. It is also wise to make sure you're making your monthly payments to the bank directly. Too many cases of the car dealers taking your money and not pay the bank. You wake up in the morning and no more car.
It's a sad case of pay to learn.