Update: I finally received my refund from Chase. After submitting a detailed four-page letter and nearly 50 pages of supporting exhibits, Chase reversed the charge for the non-existent flight.
A special thank you to
@Saulius for providing me with all the critical flight data from Flightradar24. Your help made all the difference.
Moral of the story: Don’t book through sketchy or lesser-known booking sites, no matter how tempting the deal looks. And don’t assume your credit card company will automatically have your back if things go wrong, especially with Chase. If you have any doubts about a purchase, consider using a different card.
I’ve attached the dispute letter I sent to Chase in case it’s helpful to anyone else facing a similar situation.
Thanks again to everyone who offered advice and support. Your input really made a difference.