Before procedure make sure no other software related to your modem is running on PC, remove sim card from modem too
Launch Option ICERA unlocker client
Open User Account data tab, enter your username and password that you received after credits purchase. Click "Check account status". (you can buy credits here www.dc-unlocker.com/buy) If DC-Unlocker/Vygis/Rocker/Infinity dongle is connected, do not enter username and password, only click "Check Account status"
Click "Detect device" button and wait for the program to detect modem
Click on Unlock tab and press "Unlock" button
Wait for the device to be unlocked
Reconnect modem to pc, now you can use it with other provider's cards