Withholding Widowers Funds

My father died in June leaving my mother as the sole account holder of an ICICI HiSave account. She had never accessed the account online nor had any personal dealings with the bank. She's hard of hearing so asked me to help her in telephone conversations with ICICI.
They refused to discuss her account whilst I was present which made it impossible for her to communicate with them. They also said that as it was an online account they could not add me as a joint account holder. My mother wrote to them asking to close her account.
At that point they wrote back saying they would make an exception and be able to add me as a joint account holder. My mother declined their offer as the service thus far had been atrocious and reiterated her instruction to close her account.
They tried to telephone her to say they could not accept her written instruction. She could barely make out a word the poorly-spoken operator said. When I called back to ask them to repeat what they had said they insisted my mother had to close her account online - which is impossible as she has never accessed it. They have since refused to act on any of her emails as the registered email address for the account was my dead father's.
Both my mother and I have written and emailed to complain but one month on have received absolutely no response. At the end of next week we are taking the matter to the Financial Ombudsman and possibly the police.
I suggest you avoid this shoddy third-world bank.