Cash Delays Caused by MoneyGram

Hello there, my brother sent me some cash through MoneyGram, but when I went to pick it up, the system indicated that the money had already been taken out. What is the process for getting my money back? I need a solution. The transaction is marked as completed at 9:20. I haven't disclosed my personal details to anyone, so who could have possibly accessed my funds? I'm eagerly anticipating your reply.