Leakage

It is not a legal problem for consideration and obligation of experts on this platform.

Many issues are beyond legal issues and finally, relations should prevail.  You are aware that the damage was due to leakage from your owned flat.  The painting of that ceiling may not cost more than Rs.1,000/- for that room.  Consider relationships, and cut down the issue by sacrificing few amounts aa it can save you from further interference by Society and others.  Generally, no neighbor demands such a petty amount. as painting periodically is a routine process for maintenance of any flat..  They should have done it even in usual course if there is no leakage