在我打1800电话后，收到一封e-mail， 内容如下：
The status of this service request is: The processing of your case has been delayed. A check of our records establishes that your case is not yet ready for decision, as the required investigation into your background remains open. Until the background investigation is completed, we cannot move forward on your case. These background checks are required to be completed on all applicants who apply for the immigration benefit you are seeking. We will make every effort to make a decision on this case as soon as the background checks are complete. If you do not receive a decision or other notice of action from us within 6 months of this letter, please contact customer service at the number provided below.
请问这个情况怎么办？我们准备写信给congressman,有用吗？还是要告USCIS?我们希望尽快拿到绿卡，谢谢啦～