Credit Card payment is processed through a Russian bank and only in ROUBLES which adds a percentage fee to all international transactions (the amount depends on your bank). Your bank's inner exchange rate might vary from the Russian Central Bank rate on which the to make the transaction is based, and the amount on your bank statement may vary from from the original invoiced amount.
Please, when paying in Russia by card, make sure your bank knows about the payment, so that the transaction is not declined.