Why can't I send a mobile phone message after downloading a love chat with my Apple phone?

This sounds strange. You use chat software to send text messages, not mobile phones. I have never encountered such a situation. However, you said you can't send text messages on your mobile phone. You can consult your mobile phone operator to see if your short message has been sent. If you are still depressed, you can consult a talkative little secretary. This is what I do, so I know a lot.