Do repairs require a NSW Fair Trading contract?

Our new EC approved a quote for over $20K for window repairs. Since then our Strata Manager has advised the winning company is not willing to enter into a NSW Fair Trading contract for building works of $20K. Their reason being they are only repairing and not building. As chairperson I contacted Fair Trading who advised that a contract was still required regardless of whether they are repairing or building and if there was any dispute about the works if we went ahead with them, Fair Trading couldn’t intervene and the EC could be held liable.

As it was very difficult to get companies to quote on the window repairs due to the age of our complex can anyone suggest a way forward?