いつか君がした以上の仕打ちを他の誰かに受けることになるよって英語でなんて言うの？

"Haunt" is a word commonly used for ghosts. Like ghosts in a haunted house, bad things will come back to you.

haunt you = （幽霊になって）あなたに取り付く

>As you sow, so shall you reap
something that you say which means everything that happens to you is a result of your own actions.

>You will see the long-term effects of your actions.
Your actions all have consequences

>What you do will come back to you.
What goes around comes around.

"What goes around comes around!"

People who believes in Karma, lives by this rule. It means, that if you treat other people badly, it will eventually come back to you, someone will eventually treat you badly. Life is a circle!

"What you sow, you shall reap!"

This means, that when we plant tomato seeds, we expect to grow tomatoes. If we go around treating others badly, that is what we will get in return, bad treatment.

You will reap whatever you sow.
To sow - To plant
To reap - To collect or gather
This is an idiom that refers to planting and harvesting. Just as a farmer sows seeds and then reaps a harvest, whatever you do in life, whether good or bad, you will reap much more than you sowed.

I hope that helps!

You may ask this person about 'divine retribution,' as an idea that one is punished for one's actions.
Divine retribution = Divine retribution is supernatural punishment of a person, a group of people, or everyone by a deity in response to some action. Many cultures have a story about how a deity exacted punishment upon previous inhabitants of their land, causing their doom.

As ye sow, so shall ye reap (Biblical, Proverbial)
Sow the wind, reap the whirlwind = What you do to others, good or bad, will come back to you two fold, three fold, seven fold, etc (twice as much, three time as much, seven times as much, etc.).
'Sow' means to put seeds in the ground in order to grow a plant.
'Reap' means to cut and collect grains from a crop.

"Karma is a funny thing ya know....." Karma is the English term for whatever you do will happen to you. For example: Karma is my worst enemy, as bad things keep happening to me. In the first response, you leave it having as many people know what Karma is, and the meaning that follows it. Like, Karma has come back for you, or you deserve it because of what you've done.
"What comes around goes around." This is a common way of expressing what you do, will come back for you. How you treat other is the way they will treat you.