I believe this is just another predictive dialer sales call. They hang up when I answer and don't leave a message when I let it go to the answering machine.
On another 800notes post DMCR was reported as DryMaster Clean @ 972-331-7411 which is suspiciously close to 972-331-7421. Maybe it is just another extension for the same company?
Didn't answer, no message, Caller ID blank. An all-too-familiar pattern. Luckily, my call blocker supports a white list, and my phone never rings when these guys call, even though the number is not specifically blocked. If you're not invited, you either get to leave a message or just go away. Most just go away!