If you're going to tell her to stop talking on the phone, she's going to get mad. No surprise there, as she cherishes her freedom and talking on the phone. Maybe a good idea would be to give her something back in return, to make it seem like it's not a total loss. Or alternatively, you can tell maybe explain to her that you can't afford her phone bill, and that she'll have to choose between talking on the phone and doing something else that costs money. Like eating.