Electrician's men giving notice to us for non payment of their dues

We are interior designers and contractors based out of Mumbai. We had engaged the services of an Electrician for carrying out the wiring works at our various sites. His men under him has filed a complaint in a office named Shramik Uttkarsh Kamgar Sabha for non payment of dues amounting to Rs.2.6 lacs and the notice is addressed to us and the electrician. However, no supporting for this claim is there. After getting the electrician final bills during our meeting with the electrician and the officer of this organisation, his claim comes to around Rs.1 lacs only. Moreover, due to the electrician's behaviour with clients at site, we have lost our credibility too due to his bad mouthing etc. However they are demanding Rs.1.45 lacs without any supporting or justification. We have not replied anything to the notice but have had regular meetings and discussion. We would like to know if this organisation is firstly recognised and how to find this out and our legal options if any.