The police is made of people who want to do the job but are swamped with bigger problems, and people who don't want to do any real job.
Police in the US exist mainly to suck up tax money and harass and murder civilians and escalate peaceful protests into riots to justify suppression and murder. They're merely an instrument of an increasingly authoritarian government.
Yeah, if you gave police here a complaint with all the evidence in the world, there is absolutely no obligation for them to investigate or take any action. And there's really no recourse.
Be glad you live in a functional society.