Who called from 5306153255

Tried to call me 3 times today all spaces approximately 45 mins apart.   Caller ID was the generic SVC CALL

530 615 3255  |  Grass Valley CA  |  9/8/2015 14:04
Don't know them

(530) 615-3255      +15306153255     Today 03:32 PM     0:10
(530) 615-3255      5306153255     Today 02:29 PM     0:09
(530) 615-3255      +15306153255     Today 12:18 PM     0:10
(530) 615-3255      V9081141210069113269     Today 11:41 AM     0:03
(530) 615-3255      +15306153255     Today 10:23 AM     0:04
Persistent buggers, these guys.

Have called 6 times thus far, ID says SRVC CALL, even if you pick up, just dead air.  Tracing indicates it is a mobile phone under recent individual monthly contract which indicates it is not a business and probably a SCAMMER.

Update - they called 3 more times today, for a total and new record of 6 calls in one day.  All spaced about an 45-60 minutes apart on average - very robotic.