There’s a lot of replies here about why US citizens are in the situation they are but not how to fix it, which was the question you asked. You have two political parties in a first past the post system with largely similar corporate focussed policies, people primarily vote against a party rather than for one that represents them. If you really want to change things you’ll need to overhaul your voting system to break up your two party system and encourage competition from parties that actually represent what people want.

Unfortunately there is no safe and easy way to do this; it means the two parties in power giving up that power which they will not do willingly. You’ll need large scale consistent and actually disruptive protests, ie not just meeting up for a day then returning to life as nornal, but the US has a history of responding to protests the same way they do everything; with violence.

So more practically, you can contact your representative at the appropriate level of government and hope they don’t completely ignore you this time.