How do you deal with a crazy ex without hurting their feelings?

Back in November, my ex asked me to move out. Apparently he didn’t see this as breaking up, and I had to break up with him a few weeks ago. I didn’t realize he thought we were still together, but I’ve long since moved on. I’m with someone else, now.
Anyways, he called me FIVE TIMES today. I was polite as I could be, but I’m really annoyed. 5 phone calls within two hours? That’s more calls than I like to receive throughout an entire day.

I don’t really want to block him. I truly care about the kid, and don’t mind if he calls me occasionally, but today was ridiculous. What would you do?