They called me and they didn't leave a message

They've called me twice now, 2 days in a row, seem to call after 6pm local time (Alberta); don't leave a voicemail msg.  Looked up # on telus.net Reverse Directory and there doesn't appear to be a listing.

Oh, and it was 8:28pm when she (I think) called. This was the first time this person called here.

I was called yesterday from this number and there was no message left. It is a Winnepeg Manitoba unlisted landline.

someone called me once on a friday night and once on a monday night, loud noise and people in the background, but i didnt get a message on my machine,

I have been getting calls from what i suspect is this number from the information above, they each consist of 20 or 30 seconds of silence followed by a piercing tone then a computerised voice says goodbye and hangs up. I have recieved probably about 30 calls of this nature at seemingly completely random times, sometimes 3 in a day sometimes none for a week
creeeepy...