You might want to check your phone bill. I called one of those back once. Same deal. Recorded voice and then the dial tone. My next telephone bill had a $25 charge for calling some phone-sex line. Time and date matched. Bell reversed the charge, but I've never called one back since. I just let the machine pick it up...or I look it up online, which is how I found this thread. lol

Just had a call from this number.  No one answered, then a click send a female recording said "Good-bye".
Googled "ESF", nothing comes up.  When I called the number back, I only got busy signals several times.
These callers drive me crazy, always calling, and so often right at dinner time.

Picked up and no answer. Called Bell Canada to report this so that no one else has to deal with this crap!!

Just got called. I used *69 to track this number down, and then looked it up on 411. It's registered to a name and residential address. I wonder if that person's number was stolen.

call all the time

Just another supermarket man try to sell their mom's products and services.  Just do not pick up and let your answering machine does the job.

Cleaning your ducts with a thick accent?  Maybe it was this duck with a thick accent trying to clean your Windows:

www.youtube.com/watch?v=aHo7q32Hwls

Some crap company wanting to send someone to give an estimate on cleaning your ducts or something. Hard to say exactly because of the thick accent.

Who the hell is the esf? They just called me 8pm and all I heard was click and goodby from.a.female.voice

I answered just now and after a five second pause, a recorded female voice simply said one word; "Goodbye."

No answer

Just called my house. Did not pick up as caller I.d. says ESF. Tried to call back got message that the call can't go through due to network problems and that the # 416-207-9709 is long distance?? A sure sign for me that its probably Pakistani duct cleaning calls uggh!

they called my house phone around 6 pm and did not leave a msg. Caller ID said "ESF" dont know what that stands for.