I had the same experience with Agoda, my next payment with the same card was billed in my local currency instead of USD. I was always billed in USD for my previous bookings. After emailing Agoda for several days and insisting that it's not my mistake, they refunded me 10% of the booking price. I hope they will correct this issue as it's very annoying and I do not want to lose Agoda service just because of this issue.