I suspect this phone number might collect voice recognition when you say hello hello and no reply. It might be recognizing your voice to get the identity or easy access to bell mobility area or whereever voice recognition program is used.
According to my cellphone bill I made two calls to this number, which is in Canada. I don't know anyone in Canada. I got charged for 17 minutes of long distance charge. I know that I didn't make this call. It seems like I've been a victim of some kind of fraud. It took me about 30 minutes to clear this up. Hopefully, I won't have to go through that again. If you get a call from 416-774-4500, check your phone bill to make sure you're not charged for LD call you didn't make.