I had an odd experience at a coffee stall where the barista charged my card then told me it failed and did it again. Both times I had to input my pin but he only gave me the receipt of the final transaction and kept the supposed failed one for himself.
This is dodgey behavior so I checked the Monzo app while I stood next to the cart drinking my coffee and sure enough he had double charged.
Less than 5 minutes later showing him & his manager the app I had my refund! All was handled very politely and swiftly and I believe it was an honest mistake but this proves to me the values of using my Monzo card and app.
If I had used a different card I’d never have known the problem had happened and been down £10!