003275 / 003275

Receiving calls from 1-011-100-3275 and/or 100-3275 routinely. Have been unable to track the number(s) through any routinely available format. It is very unsettling.What the hell could it be...and where is it coming from??!! When the calls come in, the speaker mode of our lan line telephone turns on, as does the mail box on the headset!! (The speaker mode can be easily heard in the On position and the blinking light for messages can be easily seen.) How could the calls turn on those functions on the lan line telephone, especially as they don't appear to be related to any state/commonwealth test or warning.Note: Only once was a message found in voice mail box (which flashed as a "new message" on the face of the phone vs. a new voice mail message which is the usual designation). The voice message said promptly call the insurance (property) company. However, when I called our very reputable property insurance company, representatives said there were no logs indicated we had been called, nor was there any affiliation with the very odd telephone number dialing on the lan line. Thus, we are not entirely certain the odd telephone calls and the one 'insurance-related' message left in voice mail had a connection.)Thank you for any ideas, suggestions.