hello. its just too bad that you missed your deadline. what kind of documents that you are having difficulties with? the logical thing to do is to contact NB and inform them about your situation. You may want to search the names of the NB Representatives who came during the info session that you have attended and you'll find their respective email addresses. Yes, go ahead and dig the worldwide web.
Nonetheless, your info session attendance is valid for two years. Submit your EOI form at the NBPNP Express Entry email add and wait for them to give you another ITA (hopefully). As you have been given an on-the-spot ITA before, it is likely that you will still qualify (provided they wont take your previous ITA against you). Hope this helps. God bless on your application.