Dear Sharavan,
At the outset, let me clarify that this site is designed by a group of senior Banking Professionals to assist Bank Customers at large to provide guidance for resolution of any complain/query/grievance in respect of financial services. This site does not belong to any Bank or a regulator, which may please be noted.
I believe that by now your bank would have investigated basis your complaint and either refunded the amount to you or disposed of your complaint conveying their decision in writing. However, if nothing has changed so far, I would like you pursue the matter as follows:
Write to Nodal Officer of the bank narrating the sequence of events, including the complaint lodged by about non dispensation of cash by the ATM. He can take up with the concerned team to verify the digital and physical records relevant to the particular transactions and other transactions processed by the ATM around the time to provide you logical explanation if your transaction was successful, if not successful what happened to the amount etc. Please bear in mind that these days all ATMs are designed to dispense cash if the transaction was successful. In other words there is little scope for complaint of non dispensation of cash unless there was a power failure or unforeseen technical glitch during the course of the transaction. Contact details of the Nodal Officer can be found on the bank's website.
In case the Nodal Officer does not respond or the response is not to your satisfaction and if you are confident that you have not got justice even though your claim is genuine, you may take up your case with the Banking Ombudsman for resolution 30 days after your first complaint to your bank. While writing to the BO, please provide complete details and also enclose the communications exchanged with the bank.
For address of the Office of the Banking Ombudsman, Area of Operation (jurisdiction) and the procedure for lodging complaint, you may access the website https://bankingombudsman.rbi.org.in/
Regards
J R Mohandas