1)Should i reapply for visa---(there is no new information, but employer gave revised letter..(only the date has been changed)
2) Whether employer can send the invitation letter directly to contact Canadian High Comission & wait for feedback.
I got rejected and reason are purpose of visit, My current employment siutation ( I am unemployed) and limited employment prospects in your country of residence (what does it mean)
You can do that, apply again I mean. You pay again. But you haven't overcame their rejection points. You can not do anything about the last rejection point.
It means there are not enough jobs in your country. You are still unemployed (but you can explain that this is primarily the reason you are applying, to get employment
) Your reason for going is still the same (this is weak, as has been explained before). Faxing the invitation letter to CHC might help but it still might not be enough to convince the visa officer to believe you are going to Canada just for the interview.