If someone has wronged me, would it be backbiting if I mentioned it to others?
It is best to forgive. If you forgive, Allaah will raise your status in this world. Do not take my word for it. Read the following authentic hadith:
Abu Huraira reported Allah's Messenger (sallallaahu alayhi wa sallam) as saying:
Charity does not in any way decrease the wealth and the servant who forgives, Allah adds to his respect, and the one who shows humility, Allah elevates him in the estimation (of the people).
Also keep the following Qur'aanic Verse in mind
"… Let them pardon and forgive. Do you not love that Allah should forgive you? And Allah is Oft-Forgiving, Most Merciful."
Having said that, we have the following Verse in the Qur'aan:
Allah does not like the public mention of evil except by one who has been wronged. And ever is Allah Hearing and Knowing.
Imaam al-Tabari mentions several interpretations of the scholars for this Verse in his tafsiir
One is that if someone has been wronged, they are allowed to make dua against the person.
Another is that if someone has wronged a person he can inform of the wrong that was done to him.
My personal advice is that you forgive and reap the rewards in both worlds. If you are like me, and cannot forgive, then telling other people will not do you much good.
Make dua against the person. Remember that you are not to transgress in your dua.