Yeah, its frustrating when some cases get approved from march and January case is still pending. Some more cases have been approved from mid-late December. So, we might hear something in a month or so.
To check the case via phone you just need to call USCIS customer care service 800-375-5283. An automated voice will direct you to enter your receipt number. Usually online and phone inquiry results to same output. But in my case, online inquiry just says the case has been transferred to another USCIS office but does not say where. I received a notice regarding where my case was but automated phone says its transferred to Lincoln, Nebraska on the same date. So, my guess is, it was initially transferred to NBC and on the same date it got back to Nebraska. My other cases 485/765/131 are in NBC.