I had this happen JFK-AMS, except instead of landing in Canada we went all the way back to JFK and landed in the middle of the night. I was BIS for 3644 miles because we turned around halfway. At that point I chose to cancel my trip to Europe and was refunded completely. About two days later the miles posted for the incomplete flight. I actually got 5466 MQMs because ironically enough that wasn't even the flight I was supposed to be on and I had been rebooked in full Y. The whole trip cost me $160 for a taxi home from JFK at 4am, so my failed business trip delivered $0.03/MQM.