Purchased wrong region code.

[Krxfty]

I am kinda confused which version I should buy.

I've a EU SE account, but the POL account I use is an NA one. Do I get the NA or the EU expansion any idea?

When you say you have a NA account do you mean your SE or POL account?

I had a NA account but purchased a EU expansion, so if you're PO account is NA, get the NA version.