water seepage from floor above

Hi, i made a deal for second sale flat. Agreement not done but i have given token amount. In the purchased flat there is leakage in the bedroom. But before the deal i havnt noticed. The leakage is from above floor flat. Now i know the seepage and ask current owner(seller) to repair. But he is not willing and asked me to do on my own and not even ready to interfere in the issue. This matter wasn't discussed before the deal as i was unaware nor he told intensionally. I am not ready to do it as expense is 50k approx.Please advise what can be done. Thank you in advance.