thanks.
To clear something up. It does happen that the mail is lost somehow, believe it or not. Second, there is no previous balance, and pay in full every time. The new balance is in the new purchase, and and supposed to be on the previous statement, which is paid in full. If not listed, it is safe to assume there is no more balance. And at that time that specific company is running a promotion to reduce the credit card to $0 when you spend $0.01 or more. And another thing is if there is NO balance, they DONT send statement, it is what they doing for many years, they claimed it will save trees. There you go the story. It may not happens that often(or dont even believe it would ever happen) to those who read this and can answer question like this. Then there is no need to continue thinking, because it is impossible for you to believe in what ever is being said above. Thanks for your time.
More to add into this discussion is: Only the interest result from the late pay part is questionable. Hope that helps.