Consumers, both business and home, can be held responsible for fraudulent calls made with their account by hackers, overseas.
Look at this story in the Los Angeles Times about a customer of Spectrum (formerly Time Warner) The particular customer owns a public relations firm in Brentwood, CA. She wound up with a $6400 bill for calls to Cuba. The news story was on WJLA in DC tonight.
Practically all telecom companies put these provisions in their fine print. However, in practice, most companies have been willing to forgive calls that were obviously fraudulent.
The problems can occur with either landlines (usually digital now with cable providers) or cell. There would be a logical question if a hack could occur anywhere else but inside the telecom company, which ought to be relevant to any litigation of charges like this. But consumers may be threatened with termination of service in the meantime.
In the summer of 1995, just was hacking was getting started, one of my Visa cards was suddenly rejected at a supermarket, and I quickly got a call from the bank, about $3000 of calls from Canada placed on the card through ATT. The charges were all reversed and the card replaced. The cause of the hack was never explained.
I have not had significant charges for robocalls.
And back in Texas, around 1999, a $4000 payment made to me to settle an old problem over an assumed mortgage was stolen electronically. But it was refunded to me properly.
Hacking has been around longer than people think, even on older mainframes; companies have countered them generally by tightening application elevation procedures, a security topic that was all the rage in the 1990s, before Y2K. There were actually some security mishaps in my workplace in the early 1990s: a contractor one time stole a server, and another time an operator was arrested for embezzlement, scary stuff if it happens where you work.