Calls multiple times a day.  Never leaves a message

Has called every evening this week but doesn't leave a message. Since I am not home when they call it doesn't annoy me but it does bother me, though since it is not identified I would not answer the call anyway.

many calls - no message

Calls but never leaves a message.  Several times a day

I got a call from them on 04/17/2013. A black male voice on the other side of the phone, he said he was calling from 'Rain south' or something like that. He said that they have 3 technicians who do water testing in my 'neighborhood' for Ph levels, Chlorine, hardness etc and they have 3 time slots and asked if he should go ahead and book me for one of them (all this was said in one continuous sentence which doesn't give you time to think)... so I stopped him (ofcourse I was very suspicious) and asked him how he got my number and which company he is representing. He mumbled something that I didn't understand, so I asked again. Then he hung up. Everything about this screams 'SCAM'.