Da li mogu samovoljno da napustim posao koji mi je obezbedila Sponzorska agencija?

Ne, jer si zahvaljujući tom poslodavcu dobio/la posao, smeštaj i dokument DS-2019 na osnovu koga se dobija J-1 viza.

Can I voluntarily leave the job provided to me by the Sponsorship Agency?

No, because thanks to that employer you got a job, accommodation and a DS-2019 document based on when you got a J-1 visa.