The profile of a boy who is doing this to you suggests that he won’t give up until he is challenged directly. You have done all you could and the fact that he won’t stop and is finding ways to disrespect you means you need help from adults. If it is happening in school I recommend telling the counselor or a trusted teacher. You have done everything right and the fact that he is talking about you and not respecting your boundaries means it is time to act. Research on bullying supports this. Don’t keep trying to manage this yourself. The time for that strategy has come and gone.