One of my previous employers is not willing to give me any experience letter, stating that it is the company policy that if you leave before 12 months you can not have one. I need the experience letter for my Green Card, I140 application. Infact I am being told that I may need it before PERM as well. My question is, why is it that an experience letter is a mandatory document from USCIS, while the employer is not liable to give one? Shouldn't I be able to get the experience letter from my previous employer via any laws ?