Around 1,000 workers laid off by Iran's Entekhab group demonstrated outside the South Korean embassy in Tehran on Sunday after an acquisition deal for Daewoo Electronics fell through because of sanctions.
Entekhab had to let them go when it shut down a manufacturing line, the company said.
Three months ago, employees demonstrated at the embassy in the hope that Seoul would intervene to refund a downpayment of $70 million (53 million euros) Entekhab paid in 2011 to Daewoo.
In November 2010, the privately run Entekhab Industrial Group signed a contract sealing its acquisition of Daewoo for $518 million (397 million euros), the manufacturer maintains.
"Today, around 1,200 laid off workers from our company gathered again in front of the South Korean embassy after we did not get the money back," Entekhab's media spokesman Eshsan Fadaee said.
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Daewoo Electronics, a former subsidiary of the now-defunct Daewoo Group, has been under a debt rescheduling programme since 1999 when its parent company collapsed.
Entekhab's deal to acquire 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.
Entekhab, located in the central province of Isfahan, produces domestic appliances including refrigerators, washing machines and televisions under the brand names Snowa and Haier.
Under the punitive measures, South Korea has suspended the operations of Iran's Bank Mellat.
The United Nations, European Union, United States, and several other countries have imposed sanctions on Iran for its refusal to halt uranium enrichment, which world powers suspect masks an atomic weapons drive despite Tehran's denials.