877-630-5455

they hang up on me when I pick up. they've called severl time in one day

As soon as I start getting hang-ups or other "nuisance" calls - I immediately contact my phone service provider with an email:

Please "block" the following number:
877-630-5455

I receive a response back within 24 hours:  "That number was added to your block list"

That's it, I never receive another call from that number again! :-)

The calls are from Cox (the cable company). I recently started internet service with them and they called a number of times. I never answered the phone, and they never left a message. But they sent a follow up email letting me know they'd been calling, and that I could reach them at 877-630-5455 . I suspect they never left a message because they wanted to get me on the phone to pitch their TV or phone services, which I did not order.