Cancelling Vakalthu Nama

Sir, Our mom and Aunty signed in blank vakalathu nama file to an unknown lawyer who called us and said some details abt the property which relates was cheated by our relative and also advice that, he will help iif we give 1. Share but, its been a year, till he is not yet disclosed anything to us. We called and went but no response. We want to cancel the vavakalathu now. What is the procedure? Will it issues to us in future... We don't what wrong he has done with my family members signature? Is it possible to register and rrun a cade in court without our presence? Pls advice