The girl said to the boy, "Call if you have anything in the future, and don't send text messages. Do you have anything else to do? If not, I will hang up. " What does she mean?

This usually means that you send too many text messages and she is annoyed, or when she is doing something, you send a text message late, and she always feels that it is too much trouble to look at her mobile phone, which affects what she is doing.

So she asked you to call her and say everything once, which saved the trouble of sending text messages.

Maybe you pestered her by texting, which made her a little annoyed, or maybe she was busy with something important, and your texting affected her, so she was a little angry with you.