Bedroom ceiling leak

[Indu29]

Hi all
I woke up this morning to see damp patches.
Above my bedroom is 2 flats who share the same wall bathroom/kitchen.
I have approached both flats but none reported any leakage or any difference in their water bills.
Guttering is also blocked and flats in my building have also reported getting damp patches with rainy weather but goes away when the weather improves.
How should I deal with this situation? Should I report to the building management company?

Yes report ASAP.

Is there anything else I should do? Should I ask one of the flats above to call a plumber? I already tried asking one of them but they said they were not willing to pay for the plumber if the leak isnt coming from them...