Hi,
1) the stock is available. But is it available for the deposit that is in the order?
Another thing, it can be that you have reservations of other orders
2)
he/she has several cases:
a) I have stock, but in the moment of the consumption, I don't have more. Then I have COGI
b) I don't have stock, I tried to consume, but the system show COGI. After I received more material, I have to reprocess COGI
c)...
3) COGI
Common COGI Errors & Resolutions
4) has to solve the problem and later to reprocess COGI
5 and 6) read the article above, maybe solve all their doubts
Regards
Dimas