Lawmakers grilled KT and Lotte Card officials at a parliamentary hearing Wednesday after a string of major hacking incidents, accusing the firms of failing to set up proper security and slammed their follow-up measures. 

KT CEO Kim Young-shub apologized, saying the breaches have caused “anxiety for the entire nation,” while Lotte Card CEO Cho Jwa-jin admitted the company’s fault and pledged to minimize consumer inconvenience. 

Lawmakers criticized KT for ignoring long-standing warnings about the security risks of femtocells, which were cited as a cause of the company’s recent unauthorized billing scandal. 

Rep. Han Min-soo of the Democratic Party called for Kim’s resignation, saying that it was disgraceful that KT calls itself the backbone of the national network. 

The government said a joint task force is probing possible links between a July KT server breach and an August small-payment fraud but downplayed speculation that the hacks could produce cloned phones. 

Lotte Card, meanwhile, acknowledged delays in reissuing cards after the breach, saying requests had reached one million but would be resolved by the weekend.