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If you cancel the order after your debit card payment has been approved, the money will be withdrawn from your bank account. Then, the money will be refunded back to your account.
Also, if you make changes to your order, you will temporarily be charged twice.
The amount of time the refund will be returned to your account depends on your debit card company.