Housing society law for water supply concerns

Hi All, Need your suggestion with issue I am facing at new (resale) flat I recently shifted to. It's 4 floor society and my flat is located on top floor, since day 1 I am facing issue with low water pressure at my flat. Society releases water for 30 min daily, however in this 30 min slot only 300-400 liter of water is getting uploaded to my internal tank which is not sufficient for my family of 7 members. I got internal and conceal pipes cleared (serviced) and replaced all shafts from my end, however issue still remains un resolved. Plumber suggested that either I need to replace current 1/2 inch supply pipes with 3/4 inch pipes or use water pump. I wrote a letter to society with above summary and options, but they refused to approve either of them stating previous tenant (owner) was never having such issue when they were residing. What are my legal rights under housing society law and whom should I escalate this for solution as it's difficult to survive without sufficient water.