I had to show this to my boss, we called it "mistakes" but I know she understood that there was a deal between the seller and sales manager to steal money. She doesn't want I check more than those liquidation she said she doesn't want to know how many money she lost. The company has a contract with this seller untill next year, we can't accuse the seller because we have not proof that he knows these mistakes were in purpose. And sales manager quit the company and now he is another associate who signed a contract with us so at least this is good since fire a employee could be complicated and expensive.
This situation makes me so stressed, I'm glad I found this but because our actual situation there is not so much that my boss can do.
Well... from now we will not lose more money with this since I'm not a thief.