Hi Ramon,
Thank you very much for your email.
However, I must tell you that is Western Union who decides in which currency the payment will be. This depends on the available currency in each office.
I am sorry to tell you that we're not the ones who decide the currency in which the payments will be, it's Western Union who'll make the choice.
But if you want to always receive your payments in Dollars you can change the form of payment of your account to check, and you'll always receive checks in USD dollars.
As simple as that.
Good luck!
I hope that this solves your issue. If you still have any concerns, please reply to this email.
Sincerely,
Tomás