I got the same collections style call as well. I called within the hours specified and they never answered. Atlantic Water sounds like slime to me. They have some pretty stellar reviews about their sales practices as well.
Got a yellow card sent to call mrs. post. thanks for the info. I will not be calling either. the card says "2nd Notice" and that they were unable to reach me by phone.. I never got any calls from them. sounds like a scam.