I can only top up in USD using my Steam Wallet
Following a recent policy change from Valve, starting on November 20th, Steam will implement regional USD prices for over 25 countries (see full report here).
If you're using Steam Wallet as your payment method, the price of your transaction will now only be available in USD. If you are not in one of those countries, please contact Steam support to clarify the currency available to you.
We apologize for any inconvenience this may cause.