According to the AFP (October 21, 2012):

Around 1,000 workers from Iran’s Entekhab group staged a demonstration at the South Korean embassy in Tehran on Sunday after an acquisition deal with Daewoo Electronics went sour due to sanctions.

The demonstration by workers from the private Iranian company was aimed at retrieving a downpayment of $70 million (53 million euros) Entekhab had paid in 2011 to Daewoo, company spokesman Hamid Ghaznavi told AFP.

[…]

Entekhab’s deal for the acquisition of the Daewoo Electronics came unstuck in September 2010 when Seoul, reportedly under pressure from Washington, slapped sanctions on the Islamic republic over its controversial nuclear programme.

“When they told us that the deal will not go through due to the sanctions, we asked for a refund of our downpayment,” Ghaznavi said.

“But since 2011 they have been stalling and telling us that because of banking sanctions they are unable to pays us.”

I am not so sure the word “stalling” is appropriate – the company really has no choice.  Like the Chinese in the earlier post on North Korea – the Iranians knew what they were getting into (AFP, November 14, 2010):

The buyout by the privately owned Iranian company comes about two months after Seoul’s government imposed unilateral sanctions against the Islamic republic over its sensitive nuclear drive.

Entekhab, which along with Swedish giant Electrolux has been pursuing the South Korean company for the past year, had “purchased Daewoo Electronics for 518 million dollars,” said a report in the reformist Shargh newspaper.

A diplomat who spoke to AFP on condition of anonymity confirmed the “final contract was signed a few days ago and the acquisition of Daewoo Electronics by Entekhab is complete.”

[…]

Its acquisition of Daewoo Electronics comes after Seoul, reportedly under pressure from the United States, levied its own sanctions against the Islamic republic on September 8 over its nuclear programme.

As part of these unilateral punitive measures, South Korea has suspended the operations of Iran’s Bank Mellat from October 11 for alleged violation of foreign exchange laws.

Bank Mellat is one of Iran’s biggest lenders and its Seoul branch is its only operation outside the Middle East and Europe.