Disclaimer: The materials provided below are informational and should not be relied upon as legal advice.
I am not clear based on your description, why this person is demanding a $200 payment from you? Is she alleging you broke her cell phone? Have your broken her cell phone or done any other damage to her? Generally, demand letters are requests that are sent from one party to another party without the need to file them in the court. If you feel there is any merit to her claim, you can choose to pay her. If you do so, you should get a written release from her so she will not be able to sue you after accepting the payment. If you feel there is NO merit to this demand letter, you may choose to ignore it. I suggest you immediately consult your own attorney to protect your legal rights.