I cancelled a ticket for a refund 37 days ago and I have not yet received the refund, so, at a minimum it seems it's more than 1 month. I'll come back and update this comment whenever the refund is issued.

edit: September 26th, still no refund.

edit: October 14th, still no refund (77 days).

edit: October 28th, still no refund (91 days).

edit: November 18th, refund received after 112 days. Less than the 180 promised, but a very long time regardless.