Isn't this a violation of the Labor Standards Act?

The situation you described is highly likely to constitute a Labor Standards Act violation case.

First, if the employer did not pay 50% or more of regular wages added for overtime, night, and holiday work, this violates the obligation under Article 56 (Overtime, Night, and Holiday Work) of the Labor Standards Act.

Also, the act of not paying retirement allowances is a violation of the same Act's Article 36 (Obligation to Settle Money) and Article 43 (Principles of Wage Payment), and if the worker did not receive wages or retirement allowances within 14 days after retirement without justifiable reason, the employer may be subject to criminal punishment.

In this case, the worker can file a complaint with the competent local employment and labor office.

Complaints can be filed by visiting in person or online through the Ministry of Employment and Labor website.

If you submit materials that can prove the facts of work and non-payment such as employment contracts, pay stubs, attendance records, and bank deposit records, the labor inspector requests the employer to appear, confirms the facts, and takes corrective orders or criminal prosecution measures.

An employer who violated the Labor Standards Act can be punished with up to 3 years imprisonment or a fine of up to 30 million won (Article 109), and if the unpaid wages are large or repeated, may be subject to detention investigation by the labor inspector.

In addition, in addition to complaints, workers can claim unpaid wages through civil procedures (payment orders, civil lawsuits, provisional attachments), so please proceed with necessary legal procedures.