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, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
As regards the marriage expenses, the gold and so on: if the wife does this with her own proper consent, then there is nothing wrong with it, but it is not permissible to force her to do so; rather, it is an injustice and abuse. The Prophet, sallallaahu ‘alayhi wa sallam, said: "The money of a Muslim is not lawful (for anyone else to take it from him) unless he gives it with his own proper consent.” [Ahmad]
Other forms of injustice to her is what you mentioned of the husband's family taking the land from her, forcing her to give them her jewelry and send them her earnings, and harming her psychologically.
Therefore, it is obligatory to advise those people and remind them of Allaah, and clarify to them the seriousness of injustice. Allaah says (what means): {And never think that Allaah is unaware of what the wrongdoers do. He only delays them for a Day when eyes will stare [in horror].} [Quran 14:42]
Moreover, Ibn ‘Umar narrated that the Prophet, sallallaahu ‘alayhi wa sallam, said: "Injustice is darkness on the Day of Resurrection." [Al-Bukhari and Muslim]
As regards your statement: "…as from the above, I feel she has become a dowry to that family": we think that this is an exaggeration, and what is correct to say is that they have badly exploited her.
For more benefit, please refer to Fataawa 245665 and 85873.
Allaah Knows best.