Who called from 3050000000

Caller ID just said "United States". I'm in Canada so I did not answer. They left a message. Called back 20 minutes later and left another message. When I checked them, all it was was opera/classical music in the background. No talking, no person, no message. Strange!

Calls from fake numbers like this get automatically ignored and blocked!

Been getting calls from 305 000 0000 didn't answer but heard music on the answering machine. Bizarre

THis number calls constantly!!! Usually 4-5 within a 2 hr period and no one is there... want it to stop