Is the marriage that took place between the questioner and the girl considered legally valid, given that the girl's father refused to marry her off, and her grandfather married her off remotely after the questioner agreed to send a sum of money?

The father is the guardian of the virgin girl in marriage, and guardianship does not transfer from him except with a legitimate reason. If he prevents her from marrying, she should refer her case to the Sharia judge to marry her off or have the further guardian marry her off. The assumption of the marriage contract by the further guardian while a closer one exists is a point of contention among jurists. The presence of a guardian and two just witnesses is essential for a marriage contract.