New date is Boxing Day 26th Dec 2018. Wouldn't wait til Christmas though. Also, new date isn't a guarantee, but a date that trustee will "will make efforts to request the court to accept".
Original pdf announcement made yesterday: https://www.mtgox.com/img/pdf/20181122_announcement_en.pdf
rehabilitation claims filed after the deadline (i.e., October 22, 2018) may be acceptable.
I'm not sure I agree. The original document actually does say that the trustee will argue a case to the judge forany claims filed after the original deadline... especially considering the global distribution of potential claimants. OP himself said two things that already mean he received the message far too late: there was no phone contact to him/her, neither was informed of anything, and only discovered on his own less than a week before the original deadline.
Also says English is poor, so all this adds up. If Mt Gox can show proof they sent contact, maybe. I wouldn't say OP has no cause.