she may be talking to someone at school or you can even offer options like there is a therapist blah blah blah that I would like you to see if you don't want to see her what about so and so?
I would like you to decide to try to talk to at least one therapist or I will have to stop paying for your cellphone. You can chose to get a job and pay for your cellphone yourself but you have to attend at least 3 sessions in order for me to keep paying for you
this is a good approach.
but i didn't say to force her to go to therapy as you alluded to.