I own a top floor apartment, under a flat roof. I've had 2 leaks in my bathroom ceiling in the past 6 months, as a result of storm damage. I informed the management co. (agent). Initially they responded and promised to have a look at the roof, but didn't. The second leak came through the extractor fan in the ceiling. I informed them again. This time they have chosen to ignore me. I have paid my service charge in full. The problem is going to get worse. How do I proceed?