Dear Peter,
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.
Your anxiety is understandable. You dropped a cheque in an ATM and the cheque was debited to your account on 8.10.2015. I presume that the cheque was drawn in favour of "............Bank Credit Card No..................". If this was the case there should not be any worry. You must have received repeated follow up calls because of the time lag in accounting for the amount recovered from you. Nonetheless it is wrong on the part of the bank to harass customers like this.
I am sure you have registered for SMS banking and you would have received SMS alert pertaining to the cheque debited to your account. This itself is sufficient proof. Please write a suitable mail to Nodal Officer of your bank narrating the sequence of events and requesting a feedback on the status with regard to accounting of the amount debited to your account. You must also make it clear that there was no delay from your side in making the payment and hence bank should not levy any late payment fee/penalty.
I am sure you will receive a favourable response. Meanwhile, if you receive a call, politely explain the situation. If you still feel harassed, after waiting for a week for response from Nodal Officer, you can escalate the matter to Banking Ombudsman.
For contact details of Nodal Officer you may visit your bank's website and 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