Amex refunded my money when a UK Travel operator refused the refund. Basic Section 75 in the UK. The operator then made the refund sharpish, so Amex didn't lose anything!
There is a long form to fill in if the Operator argues. One needs to be careful with the wording.
I did it all over the phone, the form arrived a few days later, by which time the Travel operator had paid up.
Basic BA Amex card.