People visiting from Pakistan on vistor (B2) visa

They are USCIS officers, as theres no INS anymore, its all under USCIS now. Well, I would give her the copy of that reply you got from that guy in USCIS, for your reuqest to get a I-94. Most likely this will show up on their systems when she comes back, because technically your mom entered the US last time, but failed to surrender her I-94 (which she never got in the system), so the system will say she never left (and living illegally past her allowed window of 6months). You should have proofs of transactions in Pakistan for that time period, immigration stamp from Pakistan in case they want to make sure she was in Pakistan throughout that time. I am almost sure, based on what you told me, she will be allowed without any problems, but she will have to explain to them what happened. If she will have problems conversing in English, I am pretty sure the USCIS has people who can carry out translations in Urdu/Hindi at most POEs at major airports.

Next time something like that happens, you can make an infopass appointment at your local USCIS office, and get things sorted you over there.