Remove successor trustee Maryland

The successor trustee (sister) is not providing information on mother's assets of trust and where they are. Mother passed away over 2 years ago. Certified letters were mailed requesting information and to act in best interst of beneficaries with no reponse for over 2 years now. What would we need to file with the court to get her removed and to provide us with information and can we do that without a lawer.