Is horizondb publicly available for us to try as well..

Yes, though I did not give it. Apparently someone who has my contact details has given it away !!!

I was surprised that my personal data was leaked and I found my name and number listed in this website.

They get people to share their contacts from gmail and then show your data

In case you find your number listed, unlist here

Unlist | Truecaller https://www.truecaller.com/unlist