I'm hoping some of you experts out there can explain what happened to us...

Last year we flew SFO-ORD on Frontier, had a great experience and were sold on getting the credit card with enough miles to get to Cancun.

So, In January we booked our SFO-CUN tickets leaving 4/26 and returning 5/6 using our points with a stop in DEN. No problems so far.

Then in February we get an email that our reservation had changed and we should call. When I did, I was told that our return flight had been canceled due to seasonality and that we could return 2 days earlier or get a refund.

So, long story short, we flew a different carrier with similar flight times. I was in the Cancun airport waiting for our return flight when I saw that the CUN-DEN flight that was supposedly canceled (FL 71) was scheduled to depart about 10 minutes later than our original schedule but definitely still flying. Additionally, while waiting at immigration in Denver we saw folks arriving on that flight.

So, can anyone explain this? Why were we told that our flight had been canceled when clearly it had not?