Read this for calling USCIS:
https://gethuman.com/phone-number/US-Citizenship-Immigration-Service-USCIS
另外拿已经盖过一次延期章的绿卡去盖章延期需要预约吗？去年3月办renew绿卡打指纹时已经盖过i551章，下月到期。
-You need to make an appointment with the local field office, not ASC . Read this:
https://my.uscis.gov/en/appointment/v2?
