Who called from 4073853685

This number called my cell phone, and I was unable to pick it up, so I called the number back and got a message that said that this number was not a valid number.

Keeps Calling, won't say anything, hangs up, called back, "extension unavailable" , must be a scam.

caller identifies himself from florida association of state troopers.  this company has called incessantly over the last 2 months or so asking for donations. i tell them i am not contributing and to please take my name off the call list. it does no good. they just keep on calling. watch out for this scam

Called at 8:47 pm. Hung up when I answered. I've read that some of these scammers use computer calling that calls several numbers at the same time. The first one that answers causes the others to hang up.
Can someone verify this?

This scam has been going on since I was  teenager. Why are they still doing this????Leave us alone!