comments:
We had the same problem and eventually got one of these electric suction traps, which has worked the best. We still occasionally get a new generation coming in with some produce but we just run this for a few days and they’re gone again.
First of all, make sure to report it asap. Even if they don't do or can't do anything about it, you have it on record, and you've probably not lived there long enough to have been the cause of this many flies. If you're in the US, clean your drains, especially the one with garbage disposal. If they seem to be particularly drawn to your ceiling as opposed to your lighting (though it looks like it's the lighting), consider the potential that it could be your upstairs neighbors if you have any. I have this fly trap and it honestly helps a lot. You can put a cap full of ACV in it and it'll really draw them in. Just make sure to turn off all lights at night so they're drawn to the light and smell of the fly trap.