Shared water supply - When I bought the property no one told me this.

[Guest]

Hi Everyone,
Please can someone help me, I bought a maisonette, the lady also owns the downstairs. The agent who sold me the property told me I had my own mains water supply. But I have shocked to learn through many leaks downstairs that I dont.* The Landlady lets it out. She did a fit out of new kitchen and I asked her to put in a stop cock but she didn't. All through the fit out the water was on and off with no notice and variously leaking sink boiler, washing machine, leaking tap in bath ....it just goes on and on ... What can I do.