You could take pictures of the manager having sex in the pool, and then take them to the her superior. Either that, or you could take them straight to the police department and cite proof of indecent exposure and all that stuff.
If that sounds too over the top, maybe you could see her superior in person. Maybe if you don't think you could convince her by yelling(or at least get her to stop implying you are the liar); you could get her to come watch her beloved Manager during the day.
Get other residents to complain in person?
>_> Just throwing out ideas.







