Or did you buy this car privately ?
From the Ministry of Finance-Ontario
When you purchase a vehicle privately in Canada from a person who is not a GST/HST registrant, 13% RST is payable. For vehicles purchased privately within Ontario, RST is based on the purchase price or the vehicle's wholesale value (Red Book), whichever is greater. Specified vehicles without a Red Book value (e.g., off road vehicles, boats, aircraft, etc.) are taxed at 13% based on the purchase price. Specified vehicles purchased outside Ontario but within Canada are also taxed at 13% on the purchase price.
RST is collected at ServiceOntario centres across Ontario. You do not pay RST to the seller.
In some cases, you may not have to pay RST if:
you receive a vehicle from a family member as a gift
you are a qualifying foreign representative/official or Status Indian
the vehicle is received as part of an estate bequest
you are a registered motor vehicle dealer with a valid Ontario Motor Vehicle Industry Council number that is acquiring a vehicle for resale purposes
you are relocating your home to Ontario and you are bringing in a vehicle you purchased before you moved.