What if someone owes money and doesn't answer the phone or reply to the text message?

That depends on whether you have an iou. I think you are willing to lend it to him because you have a good relationship. Since you are all friends, it depends on whether you want this friendship or not. If you still want this friend, just pretend that nothing happened and you are still good to him. Everyone has a guilty heart. Presumably, he will also tell you his predicament or tell you when to pay you back. If you don't want this friend, you can go to his family with an iou, or send him a message with some warnings, but don't go too far. But if you don't even have an iou, you can just leave him some malicious words. If he still doesn't pay back the money, don't contact him again. Go straight to his elders. His parents or other elders will definitely pay him back, or persuade him to pay back.