求教一个B签延期 打指纹之前就回国的问题！！

今年6月的时候给父母申请了B签证的延期extension, 但是11月份初就买到机票回国了，最近我收到了移民局让他们打指纹的信，现在我该怎么办？是写一封信要求withdraw application还是就这么不管？
我问了USCIS的客服，他们说如果写信withdraw，就算是withdraw application,如果不写信不打指纹，就算abandon application,不管怎样，超过原来B签证有效时间的都算是over staying！

uscis跟我发的原话是：We can not make that determination, again whether you withdrew or left is as abandon you were not granted an extension. Its up to DOS or CBP to make that decision based on your last travel. You were not granted an extension therefore any time you stayed after your I-94 expired will be considered over staying.

所以请问一下 我还需要写信withdraw吗