problem in migrating Provisional ID into GSt

My previous accountant didn’t migrated Provisional ID into GSt . NEither he is giving me User ID and password When We enter forgot password option to recover my ID and password ,message comes that ID cancelled and register as fresh applicant .I have taken purchases and sales in the Provisional ID .Customer helpline people are also unable to advise me what to do.Need a firm suggestion how I can migrate and take input and output in GST