If you’re in NSW, the Strata Schemes Management Act (SSMA) prescribes that Annual General Meetings (AGM) must be held each year (obviously) on a date that’s no more than one (1) month either side of the Scheme’s original / first such meeting; so there’s no “15 month mark” – it must be between 11 and 13 months relative to the original such Meeting.
The amount of Owners’ contributions (levies) must be set in accordance with the terms of a compulsory Motion placed on the AGM Agenda, and under the SSMA be invoiced as “regular periodic installments” in accordance with those Owners’ vote on the Motion; so whilst it’s possible for Owners to vote for five (5) periodic installments per year (i.e. one regularly each 73 days) that’s atypical, but in any case the invoice should state the period for which the payment applies.
Although the terms of the Strata Management Agency Agreement that your Owners Corporation is required to have with its Strata Manager may well, such as for reasons of convenience, delegate the functions of Chairperson, Secretary, and Treasurer to that individual, the SCMA prescribes that the O/C at all times remains the “principal manager”, and that the elected office holders (above) may at any time rescind their delegations, even for a short time or for a particular purpose.
Your situation sounds to me like one of those where an Owners Corporation (i.e. all Owners) has allowed its Strata Manager to effectively take-over, and in my opinion it’s time for your elected Executive Committee Secretary to exercise their authority by either instructing the Strata Manager to immediately convene an AGM or to themselves do that without delay, and for you and like-minded Owners to concurrently prepare and submit to the Secretary (cc Strata Manager) whatever Motions you require to be voted upon (i.e. in addition to those that are compulsory).
Such a Motion could include one for the Strata Manager to, in addition to their compulsory provision of information on your O/C’s finances (e.g. income and expenditure), provide information on each Owner’s payments relative to their required contributions.
I’d suggest that you make the contributions payment no later than 30 days from its due date and in any event before the AGM because if you’re deemed un-financial then you cannot vote, and in the interim have a read through THIS publication issued by the NSW Department of Fair Trading, and Schedule 2 of the SSMA, and then get moving!
By all means post again if there’s anything I’ve missed or if other related issues arise.