All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
The Shaafiʻi and Hanbali scholars underlined that when a father commands his daughter’s husband to divorce her in return for the dower and the husband does, the divorce takes effect, yet the husband is still liable for the dower. An-Nawawi wrote:
"If a man said to his son-in-law, 'Divorce my daughter and you are not liable for her dower,' and the husband does, then divorce takes effect, yet he is still liable for the dower whether the wife was an adult or under age because if she is an adult, she has the right to dispose of her own wealth as she wishes (and her father has no right to dispose of any of it), and if she is under age, then her father has no right to dispose of her wealth against her best interest..." [Al-Majmooʻ]
Ibn Qudaamah wrote, "If a father asked his daughter’s husband to divorce her in return for the dower and he does, then a revocable divorce takes place yet the husband is still liable for the dower; the father is not liable for the dower because he has exempted the husband from a right that only the concerned person (the wife) can exempt him from. Hence, such an act on part of the father is similar to that on part of a total stranger (i.e. invalid and non-binding)..." [Al-Mughni]
Based on that scholarly view, the divorce has taken effect, and it is not considered khulʻ, and accordingly you are not entitled to the dower, as agreed upon. The fact that this divorce did not take place in the presence of a shaykh or a judge does not entail declaring it ineffective.
If this was not the third occurrence of divorce, then you have the right to revoke the divorce and take your wife back in marriage, and there is no need for a new contract in this case as long as the ʻiddah (post-divorce waiting period) has not expired yet. If the ʻiddah did end, then you must conduct a new marriage contract. Please refer to fatwa 82541 on the different kinds of divorce.
If the wife authorizes her father or uncle to issue a khulʻ in return for part of her dower, then the khulʻ is valid; it is permissible and valid for the wife to delegate or authorize someone else to issue a khulʻ on her behalf. Ibn Qudaamah wrote, "It is valid for both spouses or either of them to authorize someone else to conduct a khulʻ on his or her behalf, and it is valid to delegate and authorize whoever is legally entitled to conduct a khulʻ for himself to conduct it on behalf of another person and such authorization is valid..." [Al-Mughni]
The khulʻ is considered an irrevocable divorce; it is impermissible for the husband to take his wife back in marriage except with a new marriage contract. Please, refer to fatwa 88502.
Lastly, we would like to warn the guardians and parents against hastening to end the marriage bond and terminate their children's marriages when the spouses do not willingly want to do so; verily, causing separation of husband and wife is a serious and grave sin in Islam. Abu Hurayrah narrated that the Prophet said, "Anyone who incites a woman against her husband is not one of us." [Ahmad and Abu Daawood]
Allaah knows best.