I flew with another companion on June 3rd, 2023 to Vegas from Calgary International Airport. I had booked through Air Miles. When trying to check in 24 hours before flight the system gave me an error message. When arriving at the airport on June 3rd the representative at the desk advised me I had to pay for my seats (which I had not reserved) they advised that Air Miles had not forwarded the amount for the seats? I have flown through Air Miles previously and have never encountered this. I really could not dispute this as we were planning to fly that morning. The total for two seats for leaving and returning cost me $140.70. On returning to Calgary I have called Westjet and Air Miles multiple times and they blame each other. I assume somehow Westjet assigned seats as Air Miles has repeatedly told me they do not have an option in their system to assign seats. I am really disappointed about this and have concerns about future travel. I feel I should be reimbursed this amount as I did NOT reserve seats. Westjet Reservation code RYGTTT.