How do I obtain a court appointed letter to state that I am financial representative over someone that died?

I'm the closest living relative and have a death certificate. However no one will release personal info to me (bank, insurance, car etc.) Probate said to contact Legal assistance of Dakota County but no one has called me back and the clock is ticking....landlord has destroyed all personal property. Dakota County Police said I should contact a Civil Lawyer to move forward. I need a consultation. There is no will or trust...just me to handle burial.