Telecommunications provider SK Telecom(SKT) will offer free SIM card replacements for all 23 million of its customers starting Monday, in the wake of the hacking incident that compromised the privacy of its subscribers.

The service will begin at 10 a.m. at the operator’s T World retail stores nationwide and its airport roaming centers. 

SKT plans to operate an online reservation system in case of a surge in demand for the service. 

The company also plans to provide refunds to customers who have already replaced their SIM cards at their own expense since the hacking incident. 

The initiative also extends to customers using mobile virtual network operators, often referred to as low-cost phone companies, that use SKT’s network infrastructure.

In a statement on Sunday, SKT urged its customers to sign up for its SIM card protection service and pledged to take full responsibility for any damages its subscribers may have incurred.