I disagree. Even if it was meant as flirting, the repeated calls from multiple phone numbers approaches harassment, not "just hitting on" someone.

You’ve clearly never had a stalker.

The behaviour sounds almost exactly like how my stalker inveigled his way into my life and then behaved when I cut him out.

I would consider stalking closer to "harassment" than "hitting on someone".

Yes, of course, I can see how it looks like I conflated the two. But, I mean, it started out as being hit on, I guess.

Yes, and harassers - including stalkers - take advantage of the fuzziness. Including by using terms like "just hitting on" for something which is much better described as "harassment".