The number they use us a phantom number for caller ID, so it isn't the real Phone number. That's why you can't block it. My suggestion is, (if you have the option) set the ring tone for this caller ID to no sound. I recorded a custom ring tone of dead air with the mic under my pillow.
This person keeps calling my cell phone and hangs up as soon as I answer. I also looked up the number and found it to be Reaseal L Cole in Michigan. I don't know who he is but it bugs me that he insists on calling my personal cell phone and won't tell me what he wants. I wish he would stop. I now ignore all his phone calls.
I have received at least two calls a day from this number. I haven't answered it so don't know who it is but I put them on my Verizon blocked call list and it obviously isn't working.