Product: Checking or savings account

I have one personal checking account and six business checking accounts with Bank of America. I received letters regarding the six business accounts in late XXXX stating that BoA had decided to close my accounts for no particular reason other than a " business decision '', as was told to me in a BoA branch today. The letters were dated XX/XX/2019, but since they were sent only via regular mail, I did not receive them until maybe XX/XX/XXXX. BoA made no effort to send the letters or termination notice via email, text message, or through their BoA online portal message center. 
The letters state that each account will be closed 30 days from the date of the letter. I went into a BoA branch today to 1. Find out why the accounts were being closed, and 2. to either move all funds into my personal BoA account, get cashier 's checks for each account, or wire the funds in each account to another financial institution. I was told, in person, today that all of the accounts are " frozen '' and that no money can be transferred or withdrawn from any account. I was told that paper checks will be mailed to the address for each account within five business days of the accounts being closed. That means that I will probably not receive the checks until early XXXX - over three weeks from today. 
Rest assured that no strange activity has been going on in any of these accounts. They are all used to pay bills, like rent and utilities. I have had most of them for over five years. The most recent one was opened only a few months ago, in XXXX, XXXX. All of them are in good standing, have never been overdrawn, and the cumulative total cash balance of all six accounts is well over {$XXXX. 
It seems illegal that a bank can close an account for no reason whatsoever, and much more so, that they can hold a customer 's money against their will for several weeks with no explanation whatsoever than " it's a business decision ''. There are no outstanding balances, unpaid bills or problems with any of the accounts. The cash is simply sitting in the accounts doing nothing other than making BoA money on the overnight interest rate profits. And no one can give me a reason why I can not withdraw it or transfer it to my personal BoA account. The accounts are not scheduled to be permanently closed until XX/XX/XXXX or XXXX. Today is XX/XX/XXXX, which is obviously several days before that deadline. But I have absolutely no access to the accounts to pay bills, transfer funds, or withdraw the cash. Is that not illegal?? 
I demanded my money in person today in a branch in XXXX, New York XXXX, and I was refused. I filed a complaint with Bank of America in that same branch, and I have left voice messages for the regional manager, who has thus far refused to call me back. 
Not having access to over $ 300K for over two weeks will cripple my company. I will not be able to pay staff or bills. Moreover, since BoA is issuing physical checks, the checks will no doubt take 30 days to clear and become available when I deposit them into new accounts at another bank. So, I will likely not have access to 99 % of that cash for at least 45 days from today. 
Is there some way you can demand that they release my funds immediately? And more so, take action against the bank to prevent them from treating other customers in such an abusive way?