I am in the ACT, not NSW so I am not familiar with the minutiae of NSW procedure. However, it seems likely to me that the meeting has not been validly notified. If you have people who are not computer literate it seems likely that they can only be validly notified of a meeting by ordinary post.
In the ACT a minimum of two weeks notice must be given. That 2 weeks is from the date a person is deemed to have received the notice. In practice that means adding a week to the notice period to allow for postage. There are legal precedents on that.
Other things in the ACT require EC approval such as the voting form, so it is not possible to put a valid meeting notice together without a resolution of the EC to approve the form. What does NSW require of an EC before you can call a meeting? If you have not had a meeting, I suspect there will be some procedural matter that has not been attended to.
Surely the NSW Act has something to say about how committee members are elected by the OC! The committee can’t just decide that only the committee can nominate. Perhaps arrange to test this by having someone write to the committee to indicate their intention to nominate you.
On occasions like this, insisting on pedantic adherence to rules will be your friend. There are times when all is going well that you can be pragmatically a bit more relaxed but this does not look like an occasion for that.
Consider documenting the flaws of process and then making an application to the Tribunal for an order to cancel the meeting on the grounds of irregularity. That will show you are not to be messed with and force proper adherence to the Act on matters of notice of the meeting date, agenda and motions including for committee appointment.