After you file

I have no idea whatsoever about the American tax system and guys from my company helped me file online at the time. The issue is that I do not have access to my original filing, which I did in 2018 on turbotax. How can I make any amendments if I have no details about the original? Can I request this from the IRS somehow?

 

I was on a visa and no longer live there (left 2018) so I'm finding it very difficult to contact my bank, turbotax and the IRS.

 

Found information about how to return the stimulus but again very difficult to do from outside the US.