I'm from the UK but I guess the problem is the same. Very lo-tec answer here: I bought a cheap, multiband PAYG phone in the UK and I keep a small amount of credit on it. Whenever a bank or whatever sends me a verification code, it arrives in Argentina as a regular SMS. I'm regularly travelling back to the UK where I top it up, but if I didn't go back, I could still top it up over the internet.