Check you've entered your credit card details correctly. Just press the 'back' button on your browser to go back to the card input page. Correct whatever needs correcting and try again. If it still fails, contact your bank.
Delivery will usually take place between 9am and 6pm. On selected smaller items where you see this icon, you'll get a text message indicating a one-hour delivery window.
Many safes need to be installed either on a DIY basis or by a professional, especially if it comes with pre-drilled holes. Have a look at the product info.