I purchased the unlocked K800i for my replacement T Mobile phone.via myworldphone. For two weeks the phone worked with my original SIM card until I updated that software from Ericsson.com. Now it asks to Insert correct SIM card. Now I can't use the phone. Can someone help me on this one. I really like the phone. T MOBILE and myworldphone cannot help. Ericsson stated that the phone is for Austraila and I would need a NCK code. DPY 101 3040/128 R35B EN IMEI: 354271025707430