Promptly and conscientiously
Dear Rosa Gusi,
First of all, we are sorry for this inconvenience in using English to reply to you.
Regarding your concern, we would like to say that you can make payment of both service fee and stamping fee in euros.
For service fee which you pay to us for processing your Vietnam visa application form, your amount in euros will be automatically translated into USD when you make payment.
And for stamping fee which you pay at the Vietnam arrival airport to get visa stamped onto your passport, you also can pay in euros. However, we would like to strongly recommend you to pay stamping fee in USD. This helps you to avoid the unbalance exchange rate upon arrival airport.
For detailed information about Vietnam visa on arrival cost, please see our https://www.vietnam-visa.com/vietnam-visa-fees/.
Wish you all good things,