Is this a scam?

I received a call, and at first, there was no voice, but after 2-3 minutes, the call was dropped. However, the next morning after yesterday's call, the same number started messaging me on MAX: "Hi👋, I'm participating in a contest, please vote for me." I didn't respond, but he kept messaging me for a long time, even when I blocked him, new numbers kept appearing. Eventually, I blocked them all, and then everything was fine...