Is a man who divorced his wife before consummation sinful, after he stipulated to her family that they relinquish half of the mahr, because they requested the divorce, knowing that they are not forgiving of their right?

If a man divorces his wife before consummating the marriage, she is entitled to half of the agreed-upon Mahr (dowry), unless one of the parties waives their right. However, if the wife requests a divorce without any harm (from the husband), the husband has the right to refuse divorcing her until she waives half of the Mahr, and he incurs no sin in reclaiming it. But if the husband oppresses the woman and compels her to waive her Mahr without justification, he is unjust, and it is forbidden for him to take her right.