For ALL the prior positive experiences, once you have run into things that, it pretty much negates the 5x saving which is not really 5x because your card still earns a 2x at the minimum - so the difference is 3x. Now just look at how much time you have spent trying to get your refund... Personally it is this kind of "contact your travel agency" when you are in need of airlines help - be it a schedule change or a refund, then you are getting no where with your travel agency - in this case Chase flat out tells you NO that the additional 3x is not worth it.

What mia suggested you to get a material information from the airline regarding to the refund issued, probably is your only way to get the refund back from Chase short of filing CFPB complaint. The airline should be able to tell you WHEN the refund was issued, to WHAT CREDIT CARD with the last 4 digits - that is the Card Chase used to pay for the booking I believe, not your actual credit card. If it was your credit card being used to pay, that makes things easier once you get the refund details. Short of that, continue to fight the invincible battle for the "nice 5x" (really only 3 extra) earning to book flights and hotels with a 3rd party instead of going directly with the providers, with the risk of when things go bad they really go worse and worse. Good Luck.