I am confused for about my job

I am very confused for about my job.
This is my first job after I graduce graduating from university.
My major is international trade and economics. Now, I am a salesman for auto bodykit and carbon fiber parts and so on.

To be a salesman you need to have a good cooperation cooperate with factory workers. But our factory worker always works too slowly. And my order always cann't never to ships on time.
I am angry now, you know that any all salesmen get their commission his bonus by from sales.
And I need to always explain to my clients why I can't ship on time.
It is makes me upset.