The question is how did they get her phone number
From the phone book, probably. It works like this: either obtain phone directory CDs directly, or make them like this: get paper phone directory books, guillotine near the spine to make a stack of pages, pass them through a sheet-fed scanner, use OCR (optical character recognition) software to turn the names, addresses and numbers into digital data, burn to CD, sell to telemarketing companies, scammers, in fact anyone. They are freely available in Asia. There are call centers in India, Philippines, Indonesia, and elsewhere, equipped with computerised dialling equipment. The computer chews its way through millions of numbers, dialling them. If a phone answers, (and often, additionally, when the computer hears a voice) the call is routed to a waiting call center operator, who has the number and name on their screen. At this point the number is logged as a 'live' one, and can be added to a smaller, more valuable list. I get a fair number of these calls. The landline phone at my house is registered to another person called Wilson. She is Miss Wilson, although the phone book just says "E. Wilson". The phone rings, I say "hello", I hear a click, a voice says "Is that Mr Wilson?" Thus I know it's a cold caller using a British phone list. I have had the "your computer has a virus" call a number of times. Sometimes they say they are calling from "your ISP". If I ask them which one, they just guess. Other times they say they are from the "Microsoft Security Department", which does not exist. The whole idea is to find non-savvy people who can be scammed.