Can Ex employers give out your phone number?

I quit a job 2 years ago as Payroll Accounting manager. I hear the office manager is now in my office. She had a carpet cleaning company come in and do her carpets. As you know they usually ask for freinds numbers so they can call and try to get more business. The office manager gave them my phone number stating that we were freinds. My number is unlisted and I have never gave the office manager my phone number ever. I have never heard from her other than when I was at work. This means she would have had to go into my personnel files and get the number. Isn't that Illegal?