I believe that the currency used is tied to the country flag you have chosen.
Perhaps you had another flag chose previously?
If it didn't change after you changed your country, I would try clearing your cache and cookies and restarting your browser. They probably have recorded a preference for you.
If that doesn't work, write to support@chess.com for help.
I was trying to buy a membership, but the website wants to charge me in shekels instead of USD. Is there any way to switch the settings on this?