He refuses to meet up and ignores you because he isn’t interested. It’s pretty simple.

I don’t see him as immature or pathetic. He is and was very clear he doesn’t want to meeet up or be in communication with you. He remains polite and cordial saying thanks for the phone number. He sees you on
the street, he says hi and doesn’t stop-because he isn’t interested. He never initiates anything but remains polite and non confrontational.

When you ask to meet up, and the person says they don’t want to see you, you need to start showing self respect and back off. You really need to leave him alone.