@Elon Rusk It is indeed concerning if bank employees approached you at your home without your consent, alongwith the information that you applied in their IPO. There are regulations in place to protect individuals' privacy, such as the Information Technology Act and the Personal Data Protection Bill.
E-mail/reach out to the bank directly and inquire about how they obtained your personal information. Request an explanation for their actions and express your concerns regarding the invasion of your privacy.
If you are not satisfied with the bank's response, you can file a formal complaint with their customer service department. Ensure that you document all communication.
If the bank fails to address your concerns adequately, you can escalate the matter to RBI. You can submit a complaint to the RBI's Banking Ombudsman Scheme, which provides a grievance redressal mechanism for banking-related issues.
Also, approach the data protection authority under Personal Data Protection Bill.