Rule of thumb,  if they don't leave a message, it is not important.  Therefore don't stress out about it.  OK.....ok

Got a call from this number. Answered. Man said he was with Home Security and that I'd been selected for a free home security system. I said I had security already, I was not interested, and hung up.

cold call selling products

This number called me and when I answered it the man on the other end said he ws calling from a "home security system" company, the reason he was calling he said is because I had won a free wi-fi home security system. I then told him I don't even own a home so how was I picked?? He hung up and that was that. I tried calling back and it says I've dialed the wrong number. This is a scam!! be careful and don't give them any info.

I think they're foreign pieces of s.h.i.t  trying to get your home address or bank account to set you up. Just like when the elderly get scammed, The victims are told that a $500,000 dollar deposit is waiting to be transfered to their account. The scammer asks for a small deposit($500 or so) in order for the $500,000 transfer to initialize. The victims will give out their bank info (routing #; bank name etc...) and end up being swindled for all of their assets. These scammers are generally over seas.
Tip: Anything offered for free over the phone by a broken english, non-American foreign p.o.s company with no background is a scam. Do not give any personal info away. You can tell them to stick it up their brown a$$