As others have noted a quick Skype call to the PM/DM line will get your CC charged in USD for a ticket originating outside the USA, even though the ticket itself will be priced in a foreign currency. If you are not PM/DM, I would try calling the delta.com helpline; reportedly sometimes the agent booking fee is waived if you are dealing with a website issue.
One upside to tickets being priced in a foreign currency is that the change fee has been lower. TATL coach fares in Y typically cost $250 to change ex-USA, but 150 EUR to change ex-Europe (which is around $190 these days). This is automatic. I once had an agent (on the PM or DM line, don't recall) try to charge me $250 for an ex-SVO Y fare, and the system override her and charged me the USD equivalent of 150 EUR instead.