In August 2009, the USCIS issued instructions to streamline the process of making inquiries with its four Service Centers. First, customers should contact the National Customer Service Center at 1- 800-375-5283 to submit their inquiry. After 30 days have passed without a resolution or explanation, customers may send a follow-up e-mail message to the USCIS Service Center with jurisdiction over their case: California Service Center, Vermont Service Center, Nebraska Service Center, and Texas Service Center. If no response is received within 21 days, customers may send an e-mail to the USCIS Headquarters Office of Service Center Operations; customers will receive a response from this email address within ten days.