I haven't travelled internationally in a while so this is the first that I'm hearing of this.

I understand that a lot of time the lender would rather just refund the difference and eat it than bother with a chargeback, especially if it's a relatively small amount. I also understand that this is not particularly satisfying -- obviously no one wants to go through a lot of phone calls to get 50c back.

When there is a problem, in addition to the disputing the charge, is it possible to report the merchant directly to Visa? After all, it's Visa's rules that they are breaking, not the lender's.