If you pay with a debit card, the money will be immediately transferred directly from your back account.
If you cancel the order after your debit card payment has been approved, the amount will be withdrawn from your bank account. Then the amount will be refunded back to your account.
Also, if you make changes to your order, you will temporarily be charged twice.
The time it takes for the refund will be returned to your account will depend on your debit card company.