I just got a call from a man claiming that I call him several times a day, but I've never called him in my life. What could be the issue?

Obviously, I’m a little concerned about this. He didn’t say what the caller said, if anything, just that he didn’t know why I was calling him 3–4 times a day and that it needed to stop. I checked my recent calls to be sure, and I can say with absolute certainty that the calls aren’t coming from my phone.

Assuming that he’s telling the truth (I don’t see why he wouldn’t be) and that he didn’t get the number wrong, what could cause this? Is it possible that my phone was hacked? And most importantly, is there anything I can do about it? (I have an iPhone, if it makes a difference.) I downloaded a reputable security app that says that my phone is secure, but I’m not totally convinced. Any help or advice would be appreciated!