Procedure for getting the 1 month ARC extension when work permit takes longer than expected

I’m in a bit of a pickle - a couple weeks back I went to the NIA to extend my ARC and found out that my work permit is expiring at the end of October(wasn’t aware that this was a thing because I usually switched jobs before this became an issue). Anyways, I’ve informed the HR about this and they applied for an extension, but it’s been getting delayed because the WDA has been asking for additional documents.
The problem is that with the oncoming typhoon holidays it’s unlikely the appplication going to get approved in time, and I have only 1 day to get things in order.

I’ve checked around, and it seems the way to go is to get a 1-month extension.
Does anyone know what documents I need to bring apart from the usual stuff?
According to this thread, How to get an ARC renewed/extended - #35 by Abacus I’m supposed to bring some sort of physical receipt about the work permit application, but we only got an email saying WDA is processing the application.