This guy is selling hacked and keys obtained via illegal methods. Some keys will stop working.
Most of his keys can be found much cheaper at other websites, just do a search. These keys are available at least by 50% cheaper elsewhere.
http://www.mpgh.net/forum/
http://www.g2a.com
http://www.dhgate.com
Do a search on the above websites and you can find the windows and antivirus keys that he is selling at much lower prices.
Do not get ripoff by this guy. I have visited all the above three links and IMP kapitashoka is the real deal of all 4.
Then you are getting ripoff. Sorry i'm just saying the truth.
The key you are looking for available for a dollar on various marketplaces.
http://www.dhgate.com/product/wholesale-malwarebytes-anti-malware-2-0-2/196355497.html#s1-0-1aLess a dollar....... be smart don't get ripoff.