Leakage from the fan fitted area and through the wires felt when removing the fan

I had purchased a flat in the 4th floor which is the final floor of a housing company purchased in 2014. There have been leakages from the fan fitted area and other portions of the ceilings in two rooms giving an ackward look. Now the water droplets fall from the fan fitted in the drawing room owi g to which I had to remove the fan. I M unable to find out from where the leakages are and who is responsible for the same. Please advise. The construction company had in the earlier complaint had refitted the water pipes in the ceiling of all the flats in the top floor approximately 5 flats. Please advise as to what should I do and whom should I contact to have this worked out. The look of the ceilings of the drawing and one bedroom gives an ugly look to the flat.