I had a call purporting to be from my mobile phone supplier asking if I was happy with the service, the ran a security check on my address, and then said they didn't have my date of birth, at which point I got suspicious and refused to tell them, the caller got quite agitated and I ended the call. A check with the recall on my phone told me the number had been withheld, so I guess it was a phishing call looking for more details so they could clone my account.
So beware of phone calls too these days.
Giok