If there is a genuine grievance or evidence of wrong-doing there are many ways to address it.
The strata manager acts on the instruction of the executive committee. Right there you have multiple people to hear your complaint. Put it in writing. Be specific, not just a vague accusation.
The EC has to act as directed by a general meeting unless it would be illegal. The OC must have at least on annual general meeting. You can speak there. If the AGM directs the EC or SM to do something illegal then you have the written evidence you need.
If you have a complaint that is not being addressed by the SM or the EC or the OC at the AGM, or if any of the above are doing anything illegal, you can take it to the tribunal.