Upvote:1
Interesting question. I think the airline doesn't necessarily have your contact information (depending on how you booked), so the website (company) you booked through should be responsible to inform you: I recently got flights booked through an agency, and exactly the same happened. I also logged in to the airline with the booking code to pick a seat, and found the changed flights. The contact email in there was another agency's email somewhere in South America, and they probably ignored the change email if they ever got it. I changed the email online to mine, and got further change notices that way.
kayak.com et al probably get a gazillion flight change emails every day from all the flights they sold, so they potentially just ignore them - what a nightmare to match them all to the right bookings and forward them. I don't know if you can ding them for it - probably the fine print says it's your responsibility to 'contact the airline a week before the flight and verify it'.