Im no expert, but I would be asking the strata manager for all correspondance between the manager and the company. I would be asking for the assessments made, and quotes provided, by the company. I would be asking for itemised reciepts for any charges.
You could also always get a second opinion from a builder to assess the work and proivide an opinion on costs.
To note, if the owners did not want to proceed with this company who made the decision in the end, was it the executive comitee? You should probably look into how decisions are made in you scheme and what functions you have delegated to the strata manager.
But again, im definately no expert and new to strata myself. Hope someone else can provide further insights.