USCIS recently introduced new functions to its online customer service
inquiry tool, e-Request. e-Request enables individuals to ask questions
about cases pending for longer than posted processing times; instances
in which an expected notice from USCIS was not received; a USCIS-issued
card or notice with a typographical error; or a request for a disability
accommodation at a USCIS office.
As of March 21, 2014, USCIS customers may also submit questions about
USCIS-issued cards and documents that they have not yet received in the
mail. Customers can additionally check processing times and their case
status, and change their address online at uscis.gov/tools.