Complaint Review: CheapOAir

My Complaint is for CheapOAir not revealing all the information when booking a ticket and as a result, I was charged for the ticket cancellation.
Last week, we got a couple of tickets for my wife and my daughter to fly to Iran on an emergency basis as my wife's grandmother got in a coma.
We noticed that my wife's passport was expired for a month. But, since Iran does not have any embassy in Canada, we decided that she goes to Iran and renews the passport there when she gets there. I searched and I found out that every airline accepts Iranian citizens to travel to Iran with expired passports except Air Canada or the flights operated by Air Canada. I was careful enough to book a ticket that is not operated by Air Canada when booking my flight through CheapOAir. But, nowhere in the search and selection process was a mention of the flight being operated by AirCanada. When I booked the tickets and paid for them, I did notice this issue. I called to cancel the flight and got another flight that is operated by Lufthansa. However, I was told that I have to pay $1260 to change the tickets. This is not fair. Why should I pay for the mistake that CheapOAir made?

I want a full refund of the money.