Further to my post and your last post,I would be questioning the factor's rights in closing the case under the circumstances you have given. It is unfortunately not unusual for some owners of flats to ignore or even refuse to agree to pay their share of costs. At this stage the factor,in my opinion,should have taken steps,to insist that they paid their share,involving taking legal action if need be.
My suggestion is that you approach the Insurer directly (not through the Factor ),and explain matters to them.
They may perhaps take a dim view of things because of the inaction by some of the owners,which could have the effect of causing further damage,and increased costs.