Is NBFC Companies has right to check customer's bank account balance details??

I would like to know an information on NBFC Companies rights on their customer's bank account amount balance check rights. Is a NON BANKING FINANCIAL COMPANY has the right to check their customer 's bank account balance details in any manner without customer notice or without confirmation of the account holder or without permission on the same to access customer's account? If Yes what is the procedures to get information? If No how to give a complaint on the same and whom to give the complaint first....kindly suggest. It was happened to me which I hadn't expected from a well known NBFC Company. One of the employee sent a message to me as I have some amount in my second bank account which I hadn't provided to them at the time of loan submission and haven't provided them this second bank account number in writing or documented way or any other way like call / phone message / whatsapp message / in mail. But their employee revealed exact amount of my other bank balance in message and orally accepted in regional language as he had received from his corporate relations with bank (my second account holding bank). Is there any provision to disclose my amount balance by any private / Government bank to support NBFC?? Kindly suggest.