A breach notice , technically a notice to comply, requires the nature of the infraction to be specifically identified. Obviously to save confusion as to what the issue is.
If the notice you received did not have this information, I’d argue you had little chance of rectifying the issue.
Similarly, the issue of the notice does not provide the OC the right to rectify the problem. Once a notice is issued, you have a certain time to fix the issue. The OC then has to apply to NCAT for further directions.
I can see that the SM has probably erred in these respects.
So to answer your questions
Yes
Yes.
I would not pay these charges. Let the OC chase you for these costs (probably too small to warrant legal action). You will not be barred from the right to vote at meetings, as you can only be barred if you owe levies.
The SM should have made more effort to tell you of the charges and the action they were taking.