Before you withdraw no deposit bonus money or free spins winnings, you need to meet the wagering requirements. When you have completed the wagering, bonus money becomes cash that you can withdraw.
To make a withdrawal, casinos need you to verify a banking method. Casino bonus without a deposit is usually given at the beginning of your casino journey. This means you probably haven't made any deposits in that casino.
You need to make a deposit and wager it at least once. After that, you can withdraw what's left of your deposit and the wagered bonus funds.