I'm so sorry to hear your inconvenience with Samsung Galaxy Home Mini product. However, Galaxy Home Mini hasn't been officially released in South Korea yet. So therefore, the fastest way to resolve your issue are the following listed below:
1) Try resetting your voice commands. This will help bixby to relearn your voice. For the best possible results; Proceed this process at a quiet place possible and also check to see if your Internet Connection is stable and not broken.
2) Contacting Samsung Service Center located in your area or region. Contacting Samsung Customer Service might be very helpful for the issue you are going through...
3) Waiting for Product Representative's reply in this Samsung Members Community.
