Consumer Redressal

we have recently purchased a resale flat in a building constructed in 2006. when we removed the false ceiling during renovation we found a lot of water had accumaleted there due to seepage from flat above. when we informed the society, they said the flat owners above had done some renovation after which this problem started. they tried stopping the probelm with some water proofing 4 years back but it hasnt worked. they are refusing to do anything now. the seepage is right in the centre of the living room around the fan and lights. we feel this puts us at more risk. also the structure of the ceiling will be weakand due to the constant seepage. can we take some legal action against them?