Why are Scorpios such FLAKES?

I'm not trying to sound rude or anything but all of the scorpios I know are really deceitful or just flakes..They always say they're going to do something and never follow through. And there's no point in me trying to hint or call them out on it because they always deny it or come up with a million excuses? How can I handle this? I can't just cut them out of my life because it's a family member. :/