Help, False Posatives on Authorize Net?!

Hi, I'm testing my authorizenet gateway, and when I use the card number 4222222222222 which is supposed to create a declined transaction, IT ACTUALLY GOES THROUGH! :huh:and without any error message at all brings your right to the "Thank you for your business" page as if the sale was successful. Help! What hapens when I go life and someones card should be denied but the system doesn't know it?

Turn your account into production mode instead of test mode, and it will be declined properly.

Well DrByte for some reason when I first tried your suggestion it didn't work immediately. Then I after ignoring it for a few days I just tried to check out again it works and is denied just fine now. Thanks for the help, I don't know if authorize.net has a time delay before the switch out of test mode takes effect, but its working now. Thank you for your help.:D