You were walking home when a guy tried to take your purse away from you, you tried to take it back from him but failed

Suddenly you felt a presence in the air with you.. then the guy fell back and your purse floated back to you.. then revealed a man in all black clothes, blue eyes white long hair

you jump up scared then he he says.. “your not gonna say thank you?” he says quietly but it manages to give you a shiver down your spine.. what will you say?