What should a person do who got married and paid a lot of money, and it was written in the marriage contract that the dowry was a specific amount, but then discovered that this amount was not handed over to the wife?

The dower (Sadaq) is the property of the woman, and she takes possession of it herself if she is of sound judgment. Otherwise, her father, her guardian, or the guardian of the imprudent woman takes possession of it. If the husband pays the dower to someone not authorized to receive it, and it is lost, then both the husband and the recipient are liable. The woman has the right to demand it from the recipient due to his transgression, or from the husband due to his transgression by paying it to an unauthorized person. If the husband pays the dower to his wife who is of sound judgment, or to her agent, or to the guardian of an imprudent woman, then his liability is discharged. However, if he pays it to someone other than her agent while she is of sound judgment, or to someone other than her guardian while she is imprudent, and it is subsequently lost, then she may claim it from whomever she wishes of the two.