I got a phone call to make an appointment. I was a...

I got a phone call to make an appointment. I was a bit surprised, so I quickly promised something. After the phone call I was very surprised how much information they knew about me. I responded to the confirmation e-mail that I wanted to cancel the appointment and I asked where they got all my information. Never got more response. Not even after a 2nd and 3rd mail. I was even more suspected that this cannot be trusted.