Can Teachers Apply for Visa Extension on Expired Non-Immigrant B Visa While Overstaying?

Help required: two teachers on their second (90 day) non imm b (teaching) have been waiting for documents from their employer so that they can apply for an extension to stay based on teaching, the work permit hasn’t arrived and close to the expiry on their Non b’s the school stepped in at the last minute to try and expedite the process. Their visas’ expired on Saturday (1st Feb). They attended the office with the school on Friday the 31st and were told that they were ‘ok’ until Monday when they could produce a work permit ‘receipt’ upon visiting immigration today they were told that they couldn’t in fact use a ‘receipt’ and were on overstay. They now have been promised their work permits on the 12th of February and have been led to believe that they CAN overstay until they arrive. I KNOW from all the valuable information posted here that there are many ‘discrepancies’ in this scenario. I’ve convinced them to let me post here so that they can get some solid advice in what is a very serious situation. As I see it their non imm b’s are now expired and an extension can it be applied for on an expired visa and whilst on overstay? I’ve put forward what I know, but they need to hear it from the pro’s. Constructive advice only please. TIA