|Subject: No Dynamic Currency Conversion Please|
I had a similar sort of thing happen on my Master Card in the UK this summer. It was for a trip on Ryanair, which came back in dollars and ended up being nearly $50 (Cad) dollars over the normal rate of exchange - which was almost half the fare. And another charge, that went through in sterling, ended up costing much more than the rate of exchange at the time. When I questioned Master Card they said there's a service fee on top of everything ... so I lost my temper.
Naturally it didn't get resolved but I will no longer use a credit card while travelling unless it's an emergency (like being rushed to hospital in Port Moresby, Papua New Guinea, with no PNG kina in my pocket; but at least there they tell you up front there's a service charge for using a credit card, which of course is on top of the card's service charges).
Another irritant is that you have to fight incorrect billings within 3 months of the statement date, which didn't do me much good on my year's RTW. When I got back I noticed one charge that was incorrect - very incorrect - and had the receipt to prove it but MC refused to do anything about it.
Thank heavens for travellers' cheques ... might be old fashioned but they can always be changed and at a better rate than cash. And if they're stolen they are replaced almost immediately. I had both Amex and Thomas Cook cheques stolen in Kenya and didn't find out about it until I was boarding a flight to Mumbai. I contacted Amex as soon as I landed and had a refund within 3 hour. Thomas Cook took 4 days, but at least I got it all back.