回複：綠卡的簽證費交了，還要繼續等排期嗎？

You should have a GuangZhou case number, you can use that number to call NVC or GZ consulate. Read the notice again, maybe the notice that allowed you pay visa fee (you cannot just pay because you want to, you must first be allowed to pay, or they won't accept your money) that notice may also have instructed you to send application document. If so, you must print out the forms on your own and send the package with payment coversheet. NVC doesn't send blank application forms anymore unless you request them to.