Depositors in a bank do not have any legal right to return of their funds

 Even if the terms of the account say funds can be withdrawn whenever the customer chooses, the bank can refuse to allow customers to withdraw their funds if it doesn't have the cash to pay them. 

Closing the doors is the traditional way of stopping a bank run. 

Celsius, like other crypto lenders that have suffered bank runs since Three Arrows Capital collapsed, closed its doors to stop customers withdrawing their funds. If it hadn't, it would have run out of money. 

Furthermore, if the bank goes bankrupt depositors are only entitled to a share of the residual assets after all secured and senior claims (such as unpaid taxes and loans from central banks) have been met. This is why licensed banks have deposit insurance. 

And this is also why, in 2008, government chose to recapitalize banks, including unlicensed shadow banks. 

If they hadn't, millions of depositors would have lost some or all of their money.

Frances Coppola - July 14, 2022

https://www.coppolacomment.com/2022/07/celsiuss-failure-shows-importantce-of.html

Banks create new money in the form of deposits when they issue loans.

This is why banking is an inherently unstable and destabilising activity.

Martin Sandbu, FT 1 March 2018

The legacy of the great crash of 2008 — economic, financial and political — hangs heavy in the air: banks bailed out to the tune of £500bn; the bankers responsible punished only in the court of public opinion;

FT editor Lionel Barber 23 November 2018

https://www.internetional.se/banks.htm