Law / I bought car in Poland, but I can't register it in Italy!! [3]

Hello Friends,

I am Lukas from (Lithuania, Kaunas), but currently I am living in Italy (Venice). 2 weeks ago I bought sport car from Polish private seller in Krakow. I bought by google translate help because my Polish language is not good, seller English language also not good. When I bought car I get from seller owners book (Karta pojazdu), blue technical date passport and sales contract. Seems everything ok. I drive this car from Krakow to Venice and everything is ok. Today I take car to my local registration office to register it and registration office on website historiapojazdu.gov.pl see that car is registered in Poland. Shows - "status rejestracji: zarejestrowany". Seller tell me he informed his local registration office and give them sales contract that car is sold in Italy. And he don't know why on this website write that car is registered still in Poland. Maybe you know what I need to do that car will be unregistered from Poland?

Thank You