Question:

Somebody at work spread false rumors against a colleague, an ignoble deed that caused the former some harm and anguish. The slandered and disgruntled man returned the favor to his attacker by doing exactly the same to him. What is the ruling in this?
Answer:

Each of them has wronged the other, and each one of them should ask the other to absolve him for the wrong. If that doesn’t happen, then it is Allaah Almighty that will judge between His servants on the Day of Judgement. Both of them should also sincerely repent to Allaah Almighty.
Permanent Committee for Research and Verdicts
http://fatwaislam.com/fis/index.cfm?scn=fd&ID=200

We ask Allah to pardon us our misdeeds and grant us Jannah with ease.

Even if you do the so called good deed their is no guarantee it would take you to Islamic paradise

So why not just satisfy your conscience after all it's same allah that gave "prophet musa" an eye for an eye law

Sahih al-Bukhari 6464

Allah's Messenger (ﷺ) said, "Do good deeds properly, sincerely and moderately and know that your deeds will not make you enter Paradise, and that the most beloved deed to Allah is the most regular and constant even if it were little."