I have locked my account and now I want to delete it form my Iphone

Have you tried using this link?

Apple ID - If you forgot the answers to your Apple ID security questions

If necessary, If you are the original owner, take the device, the original purchase receipt with the serial number, and a photo ID to the nearest Apple Store.

Genius Bar Reservation US

or contact Apple ID Support. They will need to see the original purchase receipt/paperwork also.

Apple ID Support

Apple ID Support (2) 

Apple Support by e-mail or chat         Select your device, Battery, Power and Charging, then Power adapter not working to get a chat option. 

Apple Support using Twitter

Or fill out and submit this form.

To be able to remove it from the phone, you will need to unlock your account. How did you lock the account?