If you haven't violated the Terms of service, but you see the following message:

"Sorry, but you've been blocked due to unusual activity. Please, contact us at kari@quintadb.com if you believe there is mistake."

Most probably it's a virus integrated in your web-browser. 

Some viruses may send requests to our website. The system blocks them and shows you this message.

To make sure, you can try to open same page in another web browser or another device. 

If it's ok in another browser, then you have to check your browser extensions and plugins and check your PC for viruses.

If that doesn't help, please contact us.