I called him, but he didn't answer. Always texting and saying I can't answer the phone. How can I call you back later?

This situation may mean that the other party is busy and can't answer the phone right away. They may send a text message saying "I can't answer the phone, I'll call you later" to let you know that they will call you back as soon as possible.

If you are worried or confused about the other party's reply, you can consider contacting them later or sending a text message to ask about their situation. If you are worried, you can also consider calling the other party directly to see if the other party needs help or has something to solve.

Please note that some people may prefer to use text messages instead of phone calls, so even if the other person has sent you a text message, it doesn't necessarily mean that they won't call you in the future. The best way is to wait patiently and contact them when necessary.