Galaxy Note 2 Locked I was in 4.1.2 of Samsung Galaxy Note 2 which I unlocked using *#197328640# but today I updated to Kitkat Based DN3 ROM. It says "Emergency Calls Only"

Is there a solution out? How about unlocking? DO I have to buy a new IMEI or is it free?

Any help will be highly supportive. Thanks
If you want to have any cellular functions apart from placing emergency calls, you have to have an actual cellular plan through a carrier. 

Picture it this way: If you buy a land line phone for your house, take it out of the box, program speed dials, and set it on your table without plugging it into a phone line, you won't be able to receive any phone calls. Your cell phone is simply a tablet until you activate a cellular plan through your carrier for it. 

Also, the ability to place emergency calls is a feature on all cell phones that is not dependent on carriers.

Here is a list of UK Carriers.