I'm a senior three now, and my deskmate borrows my mobile phone to send text messages to her partner every day. I don't want to bring my mobile phone, but the mobile phone fee she paid is still useles

I'm a senior three now, and my deskmate borrows my mobile phone to send text messages to her partner every day. I don't want to bring my mobile phone, but the mobile phone fee she paid is still useless. How should I talk to her? It's really a bit difficult, 1. You can tell her face to face and give her back the money. I don't think you will. Reducing the frequency of carrying a mobile phone and making her less dependent on your mobile phone is easier to accept, but it takes a long time. You can recommend her to write to her boyfriend, saying that she is more sensitive and cares about you. . . That's all I can think of. I hope I can help you.