Every time you point a finger, three will point right back at you. Someone may seem like a pushover at first but engage with them in combat and they will reveal an edge over you you could never have anticipated — it is always the quiet ones isn’t it? In a nutshell, any plan on your part to play dirty (even if you think it is justified) is going to blow up in your face, even if you think you have someone outnumbered. You are being warned to keep away from confrontation and petty politics.
If you already did go ahead with something that wasn’t strictly a good deed, you might now be facing the consequences. If you believe in divine will of any sort, then recognise that defeat is an act of divine love. Just like good parenting requires a small amount of punishing children to inculcate in them the good manners and discipline that will make them socially well-adjusted people, so too circumstances are engineered at a spiritual level sometimes to teach us important values of humility and sensitivity. In this case, because one got embroiled in petty oneupmanship.
Also, beware of someone who is looking to profit from your misery and therefore take any advice to remain fighting back in any nasty situation with a pinch of salt.