The bank has taken the step.
You may initiate your action as suggested by learned members.
Write to MD of the bank Aditya Puri ,aditya.puri@hdfcbank.com at the registered office address and mention all the relevant details, and mention that you have been willing to pay the principle amount but the bank never supplied you the bills, and ask for the original bills,and certified copy of the documents procured from you including the form signed by you,immediately,and to withdraw the withholding of your salary, immediately.You should highlight the mental tension, harassment,illegal action,unfair practices of the bank.
You can ask for call log data, call recordings, copy of charge slips signed by you .
You have the option of moving Banking Ombudsman, and lodging a complaint with RBI,consumer court.
Your counsel at your location can help you.