Is it obligatory for someone who has authorized another to pay Zakat to pay it again if they doubt whether the agent paid it?

The basic principle is that the financial obligation of the wealth owner is discharged if he pays it to a trustworthy and reliable person to disburse the Zakat on his behalf, and he is not required to investigate unless there is an indication that gives rise to suspicion. However, if it becomes clear that the agent did not disburse it, the wealth owner is obligated to disburse it a second time. And if the wealth owner doubts whether the agent disbursed the Zakat, he must disburse it; because the basic principle is that the obligation remains, and it is not discharged except with certainty.