It’s worth remembering that no one has the power to upset you, unless you give it to them.
That isn’t to say that there aren’t awful people out there. They just can’t get to you unless you stoop to their level and let them.
It won’t resolve anything if you try to fight back at them, hoping to give them a taste of their own medicine. Someone that wretched is also most likely to be an expert victim. Stooping to their level doesn’t resolve anything. It merely turns you into someone just as awful.
Hold onto your power. Rise above any situation involving them, and you’ll find that they’ll eventually creep away to look for someone else to torment.