How long can stay if in case I 539 gets rejected?

The answer is that you can stay until the date authorized by the Department of Homeland Security (DHS). Once the I-94 expires, your authorization has ended and you are no longer lawfully present in the US. Now we recognize that offers working for the DHS are generally not going to come knocking on your door within hours of your I-94 expiring. As well, if you have filed a Form I-539 prior to the expiration of the expiration of your last issued period of authorized stay, the law provides that you are authorized to remain pending a decision on that application. Also keep in mind that there may be consequences of remaining in the US. First. You may become subject to removal and deportation and this means that you can be arrested, detained and physically removed. Second, you may face the automatic cancellation of any non immigrant visa upon which you traveled to the US if you remain in the US for a period of time in excess to the period authorized to you by DHS when you arrived. Finally, you may be in eligible to return too the US if you remain in excess of 180 days in the US without authorization. The myriad of problems that can apply really call for you to discuss your situation with an attorney BEFORE you violate the terms of your authorized period of stay. So look for a licensed, competent and knowledgeable attorney who can listen to you, assess your situation and provide a detailed explanation of what steps may be available to correct the problems which may apply to your situation. Be careful out there. There are quite a few legal service providers that say and do just about anything to convince you that they can help.never give money to anyone without a written contract for services and always make sure you understand the agreement before signing it. You are the best judge of character, find someone you can trust and someone who is not going to take your money and disappear. Good luck.