It used to be that it took a while for miles to be returned, unless you called. Maybe this changed?
FWIW, I cancelled via call center on Jan 13th (2nd part of a return ticket), got the miles back immediately, got a refund receipt with a seemingly correct amount of taxes on Jan 15th, but have been waiting for that post on my CC statement ever since. I filed a claim on Jan 27th, called for an update a few days ago and was told I'd have an update in a few weeks. Ridiculous. Will probably initiate a chargeback if not resolved next week.