lost iphone 6 plus but want to block people using it

Hi team,

my iphone 6 plus was stolen in paris metro, i used lost mode and also erase my iphone content ( i am not sure this is the right method). but find my iphone app didn't show my iphone 6 plus anymore, but i saw my https://appleid.apple.com/account/manage I still have iphone 6 plus sign in. please advise how to block the people using my iphone 6+? Thanks.