they're back at it again !!

Called several times - no answer. Now, I just pick up receiver and hang up. I've done this to a number of these types of calls and they gradually stop calling.

rang 3 times and hung up no message

Called this morning just before 11, I ask who was calling, and there was dead air, then a male asked for Mrs. {mom's surname}. When told she was unavailable, the male on the other end said "oh" and nothing else. I hung up on him. He did not give a company name or any indication for the call.

Caller ID said RAJEEV VERGHESE.  When I answered, there was nothing but dead air.