shawn2013 wrote:But in his passport is written nov 2014,he stay legally upto that time and work more than 20 hours right?
He went there as level 3 but due to the university fault he admitted level 2 then he asked the university to review again and after that they promoted him to level 3,it is not his fault that he got more visa.
No. He cannot stay or work on this visa legally. If there is no applicant's fault, there is no UKBA fault as well! They provide visa according to information provided and, they will curtailed his visa according to information provided!
Regardless whatever dates written in your passport for whoever's fault, if your studies has been finished early, these dates are no more valid as you came here for the purpose of studies and that purpose is finished now. Your university must been informed to UKBA regarding this and usually, UKBA issued visa curtailment letter within few days. You may not received that letter due to some reasons like postal services or address issue (which mostly happened with students in cases like this).
But officially, your visa may over in records and if you stay / work anymore on this visa, you are actually destroying your immigration history as an over-stayer or illegal worker. etc. So its better you start to count your 60 days now and make arrangements to leave or visa extension.