Anyone know when they will contact you regarding cancellations?

I booked a ticket for December 09 back in March and found out by chance that my flight was cancelled. When i called them to confirm if it was true, they said it was, but never bothered to inform me! And they wouldn't send the new flight ot me in writing....shady!!

How often does this happen with them? Should I call and verify all my flights every day in the month leading up to them? I'm flying 3 segments with them throughout Argentina.