Presuming you have done all the termination steps properly, and it sounds like you have (a resolution to terminate need only be done as a majority decision of the OC, note that is not the EC).
This is the relevant provision of the Act. Tell the Strata Manager in writing that you require him to hand over the records or you will lodge a formal complaint regarding his conduct with Fair Trading.
https://www.austlii.edu.au/au/legis/nsw/consol_act/ssma1996242/s105.html
I’m not sure why you went to mediation.