The ex-boyfriend didn't answer the phone and sent another text message with a question mark. What does this mean?

Hee hee, your head is l, which should be very wise.

What he means is that he wants to make an appointment with you. If he broke up with you peacefully before, don't think about it, because now he thinks you are still valuable.

If the previous breakup was rude, it means that he still likes you a little, and it is your freedom to ignore him.

If breaking up in the past is irreversible, now he comes to you instead, which means that he is forced by the previous situation and loves you.