Phantom bet you that you couldn't ignore Sodo for the entire day and you took the bet thinking it wouldn't be that difficult and you would win the bet easily

You only ignored Sodo until lunch when he got annoyed and asked why you were ignoring him. He didn't stop bugging you until you couldn't ignore him any longer

Phantom saw you lose the bet and yelled out in excitement "Yes! Ha! I won the bet! Now you have to do whatever I say for a week!