Hi Can I fax over a bill of sale so I can import a car into Canada 72 hours prior like I did in the past

No, Google automated export system. (AES). It is the new way to get your paperwork processed. You will still need to stop at Customs, and send it in at least 72 hrs in advanced.

An individual from Canada was purchasing 100 cattle panels at about 2500 dollars. He had to produce a receipt of sale for the amount before he could even come pay for it and transfer it back in to Canada.