I have been getting several calls a day to my Google Voice number from seemingly random callerids. If I answer, nobody is there. If I don't answer, I get a brief empty voicemail message.
Although the callerids are never the same, it seems likely that these are all from the same organization. The changing numbers makes it impossible to effectively block the calls.
Does anybody have any idea who/what these calls might be from, and why somebody would want to continue making numerous calls without any attempt to communicate?