I spoke to someone in your Technical Dept. about being inundated with robo calls and was told to post my problem on Forums. For weeks I have been receiving calls from various callers with the same prefix: 836 as mine. I don't answer and they don't leave a message. These have been from: Wireless CA 836-4492; Wireless Caller 836-6160; Wireless CA 836-1302; SSI 836-8034; Kay Delaney 836-1332; Windsor CA 836-8382; Sharon Shepard 836-1749. I have never heard of these people and would like their numbers blocked.
Unfortunately these are difficult or impossible to block because these calls are coming from criminal advertisers who are spoofing the phone number to look similar to yours. Calls aren't actually originating from these numbers, and they're totally random and therefore unblockable. It looks like someone has borrowed this technique because the person initially responsible for these had been shut down recently (see http://www.npr.org/sections/thetwo-way/ ... r-fcc-fine)
My advice for now is to simply ignore them (since they'll have the same area code and prefix as your number). It appears this operation is large scale enough that surely the FCC and other organizations are tracing and finding those responsible for the calls.