Contact your network carrier and ask to unlock your mobile.. or go to near Nokia service center, else go through any online service and get unlock your mobile by using unlock codes. If you have any idea to get unlock your mobile through online service means, just go through Simpleunlocking.com and give your mobile's IMEI number & other required details and get unique unlock code for your mobile at reliable price. They'll help you to unlock your mobile instantly. Also follow the step-by-step guide to unlock your Nokia C7. I hope it'll helps you more.