There is no statutory requirement for the management company to send out quarterly notices, though it is obviously not in their interest or that of the strata plan for them to omit doing so. It is normal efficient business practice to get the levy notices out in advance of the period to which they apply. They are entitled to charge interest on overdue levies, except there is a period of grace of 30 days before interest @ 10% pa becomes payable, back to the due date. There is no requirement to advise when interest becomes payable. Interest is required to be paid to the strata sinking fund concerned. The legislation makes it quite clear that owners who are unfinancial are not entitled to vote or stand for committee. Depending on what the minutes said, they may not necessarily be null and void, but when it comes to acceptance of those minutes at the next general meeting it should be moved that this abnormality be recognised.
Quite frankly if the management company can’t do its job properly I’d be looking for a new one without further delay.