ok here is my situation I actually pick up that iPhone6 and I struggle has then used his iCloud is blocked but I try to unlock it with the itunes application and elas I could have all the references the phone iphone 6 I submit you to help me to unloc

If a second-hand iOS device has been 'Activation locked' then only the previous owner can unlock it, either by providing you with the account ID and password, or by removing it from his list of devices (as he should have done before selling it) - please see http://support.apple.com/kb/ts4515

If you are unable to contact him to do this then I'm afraid you will not be able to use the device - there is no other way of unlocking it at all. Apple cannot unlock it for you.

what about that official iCloud activation website is it useful?

Useful in what way? If a iOS device is Activation Locked (as opposed to merely needing activation) then only the person who set the lock can unlock it - see my previous post.