Yahoo Text Message to recover lost password

Hello,
One of our computer group could not get into her account, or recover her password and her security question was not accepted. She was sent a text message purporting to be from Yahoo. ID showed on the phone as from Yahoo.com. This person is very naive about hacking and phishing, so when she called back, the person she talked to implied that he could fix her recovery problem, but that ther computer was messed up and could give her to a technician who could help her. She asked if she would have to pay and was told yes, so did not let him go any further,. She did however get the name of the technical company, which is efisnow.net. I just talked to the Yahoo security department, and they said they do not make outgoing calls like this and made a record of the information and name of the company.
Thanks to the people who posted the Yahoo toll-free number and security email.
Has anyone here had a similar situation like this, as I would like to get all the information about this type of situation that I can so I can pass it along to our other members. Several have had their email contact lists hacked into in the last few months.
Thanks to anyone and all who can provide any additional help.