Check google analytics ecommerce transactions

For a series of webshops with same template I have some problems: - In Google analytics of one shop there are transactions of 2 shops instead of 1. In the other there are none. - In most analytics I see a lot of transactions are missing....around 30% I think this is easy for an expert, but please don't waste my time if you 'think' you can do it. I won't appreciate that at all. And to all people who read: if you put 'vvw-hw' inside your reply....I will only view those.