Cannot find my product for sale on Amazon. Part 2

I am new to selling books on Amazon and am currently working my way through my inventory for the first time and fixing errors and sifting out rubbish etc. Most of my offers are up for sale and in the correct listing but one or two are not. The book is in my inventory and 1 is available. I have looked at my list of sold books and it is not there. It seems to me Amazon are dropping the ball occasionally. Any advice?