Since I presume you are talking about the $6-billion of Iranian money that was frozen in a South Korean Bank. a few facts need to be considered. The money was released as part of a deal that had Iran free several Americans they held, South Korea could have released the money on their own and we would get nothing.
From PolitiFact:
"First, the money hasn’t been disbursed to Iran yet. When the freed Americans arrived in the U.S. in mid-September, the Iranian money was deposited into a restricted Qatari bank account. Qatar's central bank is overseeing the funds, and Iran has not accessed the money, according to U.S. officials.
Second, the deal required that Iran would be able to access this money only to pay for humanitarian items, such as medicine and food."