Here is an option from GMail for all those who want to permanently block off an email address sending spam. The feature is called ‘Mute’ and its available under the ‘More Actions’ –> ‘Mute’.
This is one of the easiest way to stop incoming mails from a particular email address and its also effective. the feature especially comes in handy when you have subscribed to some email newsletters a while ago and you now find it increasingly annoying 
Well, the next best thing is that in case you unintentionally blocked email then you could still unmute it using the same ‘unmute’ option.
Try out this option next time when you need to block a email address and do give me your feedback on how it works out for you.
