I sent three or four messages to my so-called friends, but I didn't reply. Is it necessary to call?

If you are friends, you don't have to worry about anything directly. If you don't call back after countless times, ask your mutual friends first. After all, trust between friends comes first. If the answer is that he doesn't care about you at all, then don't contact him again, just consider the previous call as harassment ... so, pick up the phone and make a phone call!