3 follow-up emails over 2 weeks, and the potential supervisor still wont respond to me? so i have this pool of potential supervisors who I am super interested in their research.

I have formulated the best introductory email - short, concise and relevant to their research- . No response! I sent back a follow-up email which had my old email in addition to my CV, still no response! I even called , but no one picks up the phone, and whoever picks up the phone is a clueless assistant who tells me to email the supervisor and ask him/her myself. 

I even visited one the labs and spoke to one of the researcher's post-doc students who volunteered to edit my emails and told me it was a good one. But then again, no response.

how is that even possible ? I dont live in the university's city (Toronto) so I cant even stalk them in their offices.

any idea why is this happening ? 

N.B 

The time period is 2 weeks. I sent an introductory email, next week I followed up with another email.

EDIT- For those of you who tell me not to "harass" professors, it is not harassment so please use another word. It is the applicant's responsibility to secure a supervisor for Biomedical engineering program by emailing/calling potential PI . To prove my point on following up , one supervisor who works in a hospital told me that the hospital email service filtered out my email. If I hadn't called him to inquire about my original email, I wouldn't have moved on in my research knowing that his lab is indeed "full". Applicants are not expected to simply sit and wait for supervisors to "notice them" and hope for the best , I must put myself on the map. I don't see why professors don't get much heat -like I am getting in this post" from harassing sponsors for grants !
I ignore such emails all the time. And I'd feel threatened/harassed if the email writer kept emailing me, contacted my students or postdocs, or showed up to my university.

The reason I ignore them is because there isn't much to say. I don't want to give you false hope because I can't guarantee your admission (even if you're the best one out of everyone who contacted me, there are plenty of strong applicants who don't contact anyone) and so, what could I possibly tell you? It might be nice to acknowledge the receipts of emails such as yours but I get hundreds of (mostly junk) emails and your email, being from an unknown sender, gets buried in the pile, and I usually just forget to reply.

So, stop stalking professors and focus on writing a good application and getting good grades. If you've emailed them once and if the email was good, they've read it and you've done your best. Any further communication will only lower their opinion of you.

EDIT: now that I re-read your post, I'm also noticing that your style of writing is quite familiar. This style comes across as immature at best, and entitled at its worst. For example, your spelling, grammar and punctuations are not quite correct. You're also narrating in a quite dramatic way, which is not how most academics write. If your email reflects the tone in which you wrote the above post and the subsequent comments, that may have had a hand in why your professor did not respond.