sillymas

The Dolar Blue rate today, March 9, is USD $1 for around 965 and 995 pesos. Did you check what was the exchange rate when you were there? Since you just returned from Argentina, it looks like the exchange rate you received is not bad. Your advice of checking the credit card exchange rate while you're there is a good one. Try several cards, and go with the one which gives the best rate.

Some credit cards charge you an higher amount using the less favorable official exchange rate, and then adjust it to the lower amount using the MEP exchange rate a few days later. Some charge you based on the MEP rate instantaneously. I used a MasterCard for a purchase, and my charge alert showed that it used the MEP rate. It looks like your Citi card used the MEP rate, so I doubt you'll receive further discount.