Malicious, out of date, SSL Certificate causing url redirects.

I have a basic website with no requirement for a SSL Certificate (https).

Someone has added a SSL Certificate which is now out of date and everytime someone accesses the website using the https:// they are redirected to another site. The certificate was issued by Comodo CA Limited.

Where is the certificate causing this redirection and how can it be shut down?

Thanks

You will most likely need to direct this question at your hosting provider or network/server administrator so they can remove the certificate from your site/IP. The SSL certificate in itself would not cause redirection and would seem to indicate another vector such as configuration on the web server itself.