Access to Canopy Area in flat/apartment

Dear Sir, I have a canopy flat in Thane and the access to canopy is only from my flat. However the sales person who has sold me the flat showed me their other flat which have canopy and how the flat owner has maintained that. Upon possession they mentioned that I am not authorize to do any alternation or changes. Since then I have been requesting from builder multiple times to keep the canopy area clean and maintain it properly so that dirt and water accumulation should not lead to dengue larva/fungus/insect formation which will posses health risk. No reply from their side, only when i crate noise they will send someone form house keeping. In my last email i have asked them if you are not able to provide me hygiene condition i will have no option then manage it in my way. I have got the Balcony grill cut and made a gate to access the canopy so that my domestic help can clean this regularly. Now builder has sent me a notice to remediate it. so my question is - Shall i respond to them or ignore the notice or what are all other legal option I have to take control of canopy area as builder has failed to provide me hygiene in my surrounding area, Thanks for your help in advance.