South Korea’s SK Telecom (SKT) once again is facing a probe by the telecoms regulator for giving customers illegal subsidies for smartphones at its retail outlets.

The Korea Communications Commission is looking into only SKT after conducting routine inspections at the country’s three major operators, the Korean Times said.

The country’s three major operators in late November were each fined KRW800 million ($717,000) for not reducing their subsidy levels to comply with a new regulation — the Mobile Device Distribution Improvement Act which went into effect on 1 October — that sets the subsidy ceiling at KRW300,000 ($280).

Rival KT has complained that SKT has offered subsidies of more than KRW400,000 in cash rebate for the iPhone 6, Samsung’s Galaxy Note 4 and LG’s G3, the Times said.

An SKT representative said that while it has been closely monitoring the handset subsidies, it’s possible a few dealers offer the higher incentives to attract new customers.