There are 3 major reasons for your phone financed by DMI Finance to be locked. SIM replacement - When you replace your SIM the phone gets locked, however, it will automatically unlock after 4 hours of the SIM replacement. Overdue payment - Please make your overdue EMI payment using the Samsung Finance+ app to unlock your phone instantly. No internet connection for a long duration – Please keep your phone connected to the internet. In case the issue persists, please call us at our customer care helpline number – 080 64807777.