Blocking/Cuf-Off of Water Supply by so called housing association for alleged maintenance dues

I've purchased a flat in the public auction from a housing finance company in 2017 under SARFAESI. Later I got to know that water connection to my flat has been cut off/blocked by the residents/members of the same building claiming that they are the committee members of the society/association named ABC and water connection is blocked due to pending maintenance from year 2000 onwards. When I asked for the accounts for the same in writing the same was refused. I tried to submit a written letter regarding the same which was also refused to be received. Registered Post sent to the Chairman also returned stating that there is no Chairman/Secretary in the society. When I enquired further I got to know that they are running the so called housing association on the name of say ABC. When I checked the property documents that I received from the HFC, I found that housing association is registered on the name of XYZ and its an NTC duly registered. So basically this ABC seems to be the association formed by the resident members on ad hoc basis and seems to be unregistered and so illegal. I filed police complaint against those residents/members who claimed to have blocked water supply for want of alleged maintenance dues but police didn't do much other than filing a chapter case against those which is going nowhere. I filed a complaint to the municipal corporation to which I got a reply stating that they have not cut off/blocked water supply and it's society's internal matter to supply water from the terrace top. I filed a complaint to the DC who first forwarded the matter to the Police and municipal corporation and then brushed it off stating that it's a civil matter. I filed a complaint to the CMO which forwarded the matter to the municipal corporation and home department from where I've not received any reply. Kindly suggest an efficient and efficacious legal remedy.