According to the Banking Codes and Standard Board of India, if you feel that the bank is using unfair means to recover the loan, you are advised-
Lodge a complaint, in writing, with the branch concerned. Banks have a redressal cell and also usually have a complaints section on their website.
In case, there is no response from their end after 30 days or so, you are advised to approach the higher authorities of the bank (Regional / Zonal Manager) whose contact details should be available at the branch.
I f nothing works, you could approach the RBI , under THE BANKING OMBUDSMAN SCHEME, 2006 with the object of enabling resolution of complaints relating to certain services rendered by banks and to facilitate the satisfaction or settlement of such complaints. Section 8 of the Scheme allows the bank to complain when there is violating in guidelines relating to granting and recovering of loans and/or non-observance of Reserve Bank guidelines on engagement of recovery agents by banks. There are several different Ombudsman who are allocated different regional jurisdictions. You are advised to submit the aforementioned form to your local area Ombudsman-