Boarding denied due to reservation not found in system

Hi,

I would like to share with you my recent travel experience and seek your advice.

Our original flight was from Toronto, Canada to Dhaka, Bangladesh by WestJet (Toronto to Montreal) and by Qatar Airways (Montreal to Doha & Doha to Dhaka). But WestJet Toronto- Montreal flight cancelled due to mechanical issue. And it was confirmed we cannot catch our connecting flight.

Then, WestJet rebooked our flight from Toronto, Canada to Dhaka, Bangladesh by Air France (Toronto to Paris) and...

Boarding denied due to reservation not found in system