bhamrick, but do you have a UK-based account as the source account? It seems from reading the site that might be a requirement.
And I gather it was not a cash pickup?
With the uncertainty of things, if Xoom gets blocked in Argentina, maybe this service will be working. Xoom requires US-based source accounts, it seems Xendpay is a UK version of that?
Assuming no more Xoom and their giving of pesos at a good rate, if you could still get ahold of dollars within Argentina and then convert by way of a cambio, then you'd still have a good exchange rate going compared to the official one when using ATM machines.
It's shaky ground that Xoom is the seemingly only good method for a nice exchange rate if a person does not have a local account for utilizing other means.