If you are in local, you may make a visit to the Ayog and become aware of her complaint, explain your position and her stand and also you may ask her in front of the counselors about the veracity of the complaint. Let she face and answer your questions.
If you are staying abroad, how did they contact you?, did you give your phone number to her and she in turn dialed the number for them? Next time when they make a call, dont answer and also change the number at abroad. Let she become fed-up calling you, this will certainly not affect your parents in India.
Her unjustified demands need not be acceded to. She first has to learn to be adjustable and flexible in her matrimonial house and with the people, if she has scant respects for human value then she cannot keep you happy for life long even if you accede to all her demands and pressures.