Either let them play with it if you gave them permission and they are not doing anything bad like calling your contacts or texting random people. Or if you did not give them permission or if they are doing something bad with it tell them to give it back and take it away from them, and don't let them borrow it again!
since you broke up then that person will stop playing on your phone
No you can not, you have to DM someone on a smart phone.
No, he STEALS your phone.
In and of itself, it is not illegal to fire someone over the phone.
It means someone is on the phone with someone else or the phone is off the hook.
You can find out if someone is on the phone by calling them and listening for a busy signal or by checking their phone's display for an active call notification.
you can't make anyone answer the phone.
To ask someone for their phone number, simply say something like, "Can I have your phone number so we can stay in touch?"
You need to type in their phone number.
Phone Book???
look in the phone book!
To politely ask for someone's phone number, you can say something like, "Would you mind sharing your phone number with me?"