How to effectively complain against an unresponsive strata manager?

Just wondering how effective is it to lodge a complaint against an unresponsive, lazy strata manager who cannot be sacked? This strata manager is managing a block of 3 units, two of which are owned by his mates (father and son). I am left with only one unit and get outvoted all the time. However, I wanted to have some repair to my unit and have been waiting for his response for two months. Each time I write to him, it's either no reply or “he will get back to me shortly”. He cannot be sacked because the other two owners love him. My question is how can I complain against this strata manager to the NSW Office of Fair Trading? Does the latter get lots of complaints on strata managers?