I recently have been greatly wronged, mistreated and oppressed by someone very close to me, and i was just wondering..how will allah punish them?
That depends on whether you will eventually forgive them or not, and whether they will seek forgiveness or not, and whether God has a certain plan for making something good come out of the wrong they have done you. We can never predict what God is going to do next, since we do not know His wisdom and His plans. Something bad that happens now may have the greatest benefit for us ten years down the road, and a person who wrongs us now may do us a great favor in the future out of their feeling of guilt. And if they never repent and you patiently wait for God’s judgment without doing any evil toward them in return, then God can give you a great reward in this life and the next for your patience.
I recommend that you read the Quran, it has many verses that clarify these matters.