Your purpose is served. Give the advance copy of such deed required for his signature in two sets, so that he can seek either lawyer's opinion or his superior's opinion by submitting one set.
Contact the manager, and if there were any such cancellations of mortgage format in the past in the computer system, just obtain a print, change the name of the borrower, amount, and descripttion of the property. In fact, it is the duty of the banker to provide such a format of release deed as per their manual.
When you have established good relations, you should not fight with officials who had a short tenure of 3 years. You are a permanent resident with a good track record and the Bank must stay in your village. The officials are liable for transfer. Hence even if someone is not extending minimum courtesy, ignore those officials with ego and arrogance, and get your work finished.