回美证4个多月了进度一直不变

AcceptanceOn February 13, 2014, your fingerprint fee was accepted and we have mailed you a notice describing how we will process your case. Please follow any instructions on this notice. Your case is being processed at our NEBRASKA SERVICE CENTER location. You will be notified by mail when a decision is made, or if the office needs something from you. If you move while this case is pending, please use our Change of Address online tool to update your case with your new address or call our customer service center at 1-800-375-5283.我的回美证一直停留在这个阶段。不知道是什么原因？我是跟儿子一起申请的，儿子的已经寄到了。我的一直没有进展。之前老公申请过两次了，每次都是一个多月就收到回美纸了，为什么我的要这么久呢。我们当初是亲属移民出去的。