You purchased a car that only qualifies for a high interest rate.
When you purchased your car, your credit report limited the monthly payment you qualified for, at that time
You were not able to qualify for a bank loan. You may have qualified for a buy here pay here Ottawa, lease to own Ottawa, in-house financing Ottawa, in-house lease Ottawa, or a bad credit slow credit Ottawa program.
Your file was mishandled in the finance office. Many times there is inexperienced staff in the finance office. You may have been shopped around and given the first rate offered.