There's no listed means for an applicant to directly get in touch with their FO except by going on an INFOPASS (which needs to be scheduled by calling the 1800 number), or by getting an agent or EMMA to submit an inquiry to the FO on behalf of the applicant. In the past, applicants were able to visit the FOs in person for case follow up after self-scheduling the INFOPASS appointment online (without needing to go through an agent), or even on a drop in basis. Of course a lot of applicants abused that opportunity and USCIS eventually did away with it