Banks are allowed to shut accounts without reason or explanation if there are fears the account is being used – knowingly or not – for financial crime or fraud, in compliance of stringent Anti- money Laundering regulations.
If there are suspicious transaction of large amounts /international transfers , then Bank can suspend the account pending their internal investigation.
However, Bank should not close an account because of unfair bias or unlawful discrimination and without giving reasonable notice to the customer.
As Banks are working in capacity of a bailor , entrusted with your money, they are duty bound to protect it from fraudulent transactions .
So, in your case, Bank has suspended your account owing to attempt by you to transfer a large amount of money from your account. Usually Bank calls the account holder to verify the transaction, before releasing the funds, however, if they were not able to speak with you over the phone, thus it raised the red flag for the bank and they have restricted your account while pending investigation.
You can make a formal written complaint to the Bank using their internal complaint procedure regarding the restrictions imposed by the Bank, which you think is uncalled for.
You can also ask your Bank for the terms and condition of your account and check whether the terms of the customer’s account to check what the terms say about the circumstances in which they can impose an restriction on the bank accounts .
If you are not happy with response of your Bank or they haven’t responded within the time allowed, then you can escalate your complaint to Financial ombudsman,
which can be done online using the below weblink-