Called at about 10:30AM on a friday. Hung up after the fourth ring & left no voicemail. this is the third or fourth credit card scam number i've gotten calls from in the last week. they've got cell phones now. this is ridiculous.
The [***] in Congress sold out to telemarketers years ago. The legislation essentially allows robo calls. To stop phone scams is technologically trivial. Call block works however it is limited to a fixed number of callers (50 with Vonage) and it must be set manually with cooperating carriers.
A more effective solutions is for the carriers to take note of the number being blocked. As soon as the violating string (example: 762-441-2010) reaches a sufficiently high total of reported offences (1,000-2,000) the carrier shuts down the spammer.
Of course, the spammer can switch to another number --- and it too will be shut down the same way.
What makes you think it wasn't on silent? It most likely was, and she probably saw that they called after the fact. I seriously doubt that she heard the phone ringing in the middle of her class. Maybe you should set an example for others by not assuming things concerning situations you know nothing about.
Anyways, I was contacted by this number today at 10:34am. I did not answer, and didn't receive a voicemail.