Fucking git gud then, don't play solo, or inform your faction-mates that you're getting raided so they can hop on and defend. Otherwise vote for raid times.
Getting raided is part of the game, defend or die.
This is preceded by the limiting of faction sizes, and in most cases shouldn't be happening if you aren't a cuck about your gameplay. You'll likely earn yourself a raiding by killing people when you shouldn't have.