To add a data point:

KL ticket booked for flights in April/May. Canceled by the airline, rescheduled for this month. After umpteen schedule changes and cancelations by DL, always without taking the impact on other segments into account, I finally asked for a refund. Received a confimation e-mail straightaway. After a month, I sent a nudge mail. Got the usual bla bla reply, but with the addition that because of my many years of loyalty they would expedite the refund. Another month later an email arrived informing me the ticket had been refunded. A week after that, I actually got the money.

Johan