Once only back in '07, my husband did the tax refund thing at EZE. They said they'd credit his credit card that refund and gave him copies of their paperwork showing how much and a number to call should he encounter any problem. He found the process a headache and never received the refund. He then 'phoned and wrote letters to get it back. Those weren't answered or he was told something like 'oh well' (!). He's since not bothered with Argentina`s tax refund system.
Also, if you're using your duty-free allowance limit to then enter your own country with goods bought from Argentina or anywhere abroad whose total value exceeds that allowance, and you have on you receipts or tax refund documentation showing an excess, you`ll owe your own country duties and sales taxes on that.
The purpose of tax refunds at international airports is to ensure that you're not paying duties and taxes to 2 countries.
The same principle often (and should) apply when you're ordering from within your own country goods from abroad that haven't been manufactured in your country or in the other country or region with which your country has a free-trade agreement.