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Any Dukascopy Bank ALTERNATIVE gives Multi currency account

they're the worst customer support and i tried to open an account and they're asked me for documents before 13 years old
Create a fake document. Anything that old would no longer exist in any accessible database, so there is no way they can verify its genuineness.
Feed those clowns with whatever they want.
 
It is ineed a pretty obscure problem. Why on earth can't this Polish company pay you in EUR? It should not be difficult for them.

I do remember hearing of pre-paid cards issued by Polish banks that have their own IBANs and would accept PLN.

Maybe you could get one of these cards? Prepaid cards - Payment cards - Bank Millennium
Look at the very last FAQ. It says there is an account number assigned to the card allowing topups from other banks.