Not being a bonafide student is a pretty vague rejection reason. You would have to apply for GCMS notes from
www.caipsgcms.com to know the reasons in detail. You also need to provide us with your marks/percentage of all the educational qualifications that you have (matric/fsc/bscs). Furthermore, is this a diploma from Humber college? I am not sure what it is. It has to be a Master since you have already done BSCS. A diploma would not be a sensible progression of education in the eyes of the visa officer so this could be one the reasons. Kindly provide all the information that i have asked above.