This is weird...

So for the past two weeks, a random person was calling me many times throughout the day. I ignored it at first, thinking it was a wrong number (it probably is), but the person keeps calling. I answer the call, and he asks about someone I don't know, and so I tell him it's the wrong number. He apologizes, and the calls stop for a few days, then starts again. I answer again, and then I tell him it's the wrong number again. He apologizes again. They stop for a day, and then start again. I tell him for a third time that it's the wrong number, this time through text. He doesn't stop calling, even during school time. Recently, however, the calls aren't as frequent. What's going on?