These guys could be burglars! They could be just "pinging" your phone with intent to get your phone to cough-up it's GPS coordinates. Why? Just to see if your home is available to be burglarized! Never answer these kinds calls and you will drive them just as crazy. The worst thing any nuisance caller can experience is absolutely no response what so ever.
Called at 9 pm. I didn't answer cause I didn't know #.