Normall, how would the airline know? Does the TA pass customer's contact information (email, phone, language) in the PNR?

Nevertheless, in this case this is no excuse for Luxair, because I had associated this PNR to my luxair.lu record, and all the time from September to now Luxair manage to be sending me emails pestering me to go spend more money choosing a seat or buying luggage. So they knew how to get a hold of me, and they were using the email address I have on file with luxair.lu, which is different from the email address I have on file with Priceline. Yet they did not notify me of the schedule change, they notified priceline who then dropped the ball.