at anytime I've CXLed a points res it's always shown back in my acc't immediately............... that being said, did the res have a CXL date that you exceeded (ie. some points reservations are required to be CXLed 1-7 days prior to the arrival date, various dates depending on property, so if you missed the mandatory CXL date you would have blown the points refund)?

Just looking at an upcoming point res of mine it says:
You may cancel your reservation for no charge until September 5, 2012 (1 day[s] before arrival). and if I don't CXL prior to the stated date Í expect to loose the points used.............