Who called from 2674282120

I've been getting multiple calls a day from this number and its sister lines, -2121 and -2122. CID just says Philadelphia PA and they NEVER leave a message. Been calling for more than a week. I tried to call all 3 numbers back and get the same operator recording: We're sorry, your call cannot be completed at this time. Please try your call again later.  I get the recording every time no matter what time I try to call.

This number and also 267-428-2088 call several times a day and do not speak

Just called my home office line. I picked up as it looked like a local number. I picked up, no one on the other end, then a beep in my ear.

Probably some kid or idiot learning how to robo-dial. I block the # on my iPhone.