Help with tax

Hello.
I'm writing here because I'm tired of searching the web, and honestly, I don't think I'll find a better place than this.

This year and last year, I went to Miami to play in the Seminole Hard Rock poker tournaments. I won both times (one over $6,000 and the other $3,600), and both times I got a 30% discount.

I am Argentinian, I live in Argentina but I have an Italian passport and now for 2 months I also have a US ITIN.

My two questions are as follows:

1)How do I recover my tax deductions? Is it possible?

2)Now that I have the ITIN, if I play and win, will they also deduct money from my account? Or will they not deduct anything now? Will they ask me for proof of Italian residency, which I don't have since I live in Argentina?

Thank you very much in advance, and I hope for answers, as I'm lost on the subject. I know it can be recovered, but I can't figure out how.