I saw some girls who experienced the same problem so I thought it would be better to share here -
I was one of the girls who bought their 3-month subscription using COSMO code back in Oct and got the Oct box with no problem. However, I read that not only me, but some other girls didn't receive anything for Nov - not only no shipping notice, but no order confirmation from the very beginning.
So I contacted Glossybox using the online form, and waited 4 days before getting a reply, they reverted nicely and asked for a status update - whether I still didn't receive anything. I said no and pointed out that there was not even an order confirmation for me.
No replies since, but 3 days after I replied their email, I received a "Your package has shipped!!" email from this weird sender namely "US Fulfilment Center". As all my other purchases are already on their way and I have all the tracking numbers, I suspect that this is the missing November Glossybox they sent to me.
Definitely not a pleasant experience but I appreciate their effort in making things up. Though I'm not going to continue with my subscription after the 3 months (or 4 months as I "should" get one month free), because I really don't want to spend my valuable time in these kind of matter ever again.