An update on my hotel restaurant charging me DCC, Citi gave me the choice of chargeback. I said the merchant will just show the slip I signed. Then he came back said I instantly won the dispute and credited a couple of bucks to my account. It showed up a week later but on the same day as the charge was made on my statement.

Next time I will be smarter and write on the slip and take a picture. I just didn't expect it this time. I didn't actually get DCC any time in London which was weird as I expected it. I even got to use Samsung Pay a lot, although the swipe was disabled on many readers and could only use NFC.