I just got off the phone with JetBlue to cancel my November flight to SXM also, but they would only credit my airfare to their travel bank, good for a future flight as long as I book by 9/12/18. However, I already have a travel credit with a different airline that must be booked by April 2018, and thus did not want another travel bank. So, I am curious what "magic words" you said to get a refund to your credit card.