At the time, Mey said, she didn't make a connection between that call and the collectors. But then she learned the call hadn't come from the local sheriff's office, after all. The caller ID had been manipulated to look like it did, a practice called "spoofing," later proven in Mey's case through phone records.
That's when she went online and discovered complaints about RFA debt collectors pretending to call from sheriff's offices, including a male collector who called women vulgar names.
"He picked the wrong person," Mey said.
You see, Mey has battled big companies over intrusive phone calls before. In 1999, she won a class action lawsuit against a major telemarketer whose salesmen kept calling people, even when asked to stop. People magazine named her one of the "Most Intriguing People of the Year." That's why Mey has recorded her phone calls ever since.
Mey said it took her a year to find attorneys who would sue on her behalf. Wheeling lawyers Martin Sheehan and Patrick Cassidy took the case knowing they would probably never get paid.
"Yes, I like to make money, " Sheehan said, "but at some level there's something so atrocious you have to let people come into your office and say, 'That's wrong and I'm going to do something about it.'"
In May 2011, Mey sued RFA for harassment and illegal collection practices. That August, RFA's lawyer failed to show up in court, so Mey testified unopposed. The judge called RFA's actions "malicious" and ruled that all of the allegations were true. And then he awarded that record judgment of $10,860,000.
When ABC's "The Lookout" went to RFA's Orange County, Calif., office to ask about the case, it was abandoned. RFA is an arm of a company called Global AG LLC. Records show it is just one of several collection companies run by the same people that often change names and move.
"The Lookout" also visited other offices registered to people named in Mey's suit, but employees refused to talk and asked us to leave.
ABC News contacted RFA's original lawyer last year, who said he was speaking on behalf of company principals Thai Han, Jim Phelps and Stewart Phillips.
"My clients say it is not their policy to engage in conduct that violates the law," he said.
He characterized the $10 million judgment as "unfair." That lawyer no longer represents RFA, Global or its owners.
At the time, the lawyer told ABC News that RFA made the first collection call to Mey, but denied making the second, obscene call.
However, Mey's attorneys had proof. They subpoenaed phone records that showed the obscene call originated at the debt collectors' offices, went through a service that faked the sheriff's number, and then arrived at Diana's house.
The collectors now have new lawyers, and ABC News contacted them, but some didn't return our calls and others declined to comment.
Mey knows she may never be able to collect the $10 million judgment awarded to her, but said her lawsuit still serves a purpose.
"I hope that it sends a message to other debt collectors out there that you have to follow the law," she said. "Because if you don't, there are going to be people out there that are going to stand up against you."