Getting tons of calls from unknown and getting random messages after

Hello! I don’t think this is a problem with the software on my phone but there’s this one number that keeps calling me “unknown” and no caller ID, I didn’t answer because I don’t know them. After that I kept getting messages that had disturbing information, by that I mean bad words, and faces I do not know, I blocked, deleted and reported the messages that I gotten, they haven’t stopped. I haven’t been on any website where my information is leaked, so I don’t know how these people are getting my number. This never happened with my iOS devices, so that’s why I’m on here wondering if it’s me that has the problem or something is just going on. Yes, I’m also thinking of changing everything is this continues