This number keeps calling me. Ive cvalled it back 3 times but always get a general vm.

Called mid day and left no message

Called my work number in the middle of  the day.  I waited while the rest of the folks in the call room chatted in the background, then hung up without leaving a message

Yeah, this number calls a lot, but you sound like you know a lot, even too much, did you used to work for them or something?

The organization is a contract agency that does telemarketing for larger corporations, and sets up phone conversations for sales representatives. Employees are required to make 160+ dials a day. At some point you're phone number has been linked to the line of business you're doing, and you're now in their Salesforce system to be called. They don't leave voicemails because usually people don't call back, but one way to make it stop is to answer and ask not to be called in the future. They will enter this into Salesforce so it pops up each time and the note will be associated with your contact name.

I have received unwanted/unsolicited calls from this number for over 8 months now.  I never answer them, they leave no message.  I'd like to block them from AT&T.

Called my cell and hung up when I answered

Missed call, no message.

Returned call and was told to leave message.  I did not.

Called cell and no message

Called cell phone and left no message.

We just got a call into our service line and I grabbed it and was a woman named "Sue Sullivan" who asked if we are a QNX customer (a type of operating system - we are in the PC business) and after answering she said that was all she needed and hung up... who are these people?

Missed the call, no message was left.

Called and left no voice message.

Got a call again from the same number, he asked again for my web address, when I mentioned he had called once already, I inquired what he needed he said it was a research project, when I continued to ask, he refused further answers and hung up...