When your website is compromised, there are a number of things that you will need to do, to get back up and running.
Applying a band-aid
To get your website running again as fast as possible, you can restore a backup of the site from when it wasn’t compromised. Please keep in mind that this is only a temporary fix, and there are extra things that you need to do.
Securing your website
Websites are almost always compromised via an insecure plugin or theme, so the first thing you should do is ensure that your website and all of the installed plugins/themes are up to date.
If you have a WordPress website, we have a guide containing some general security tips/practices that we recommend you follow.
Consulting a web developer
If your website is compromised and you’re not sure how to proceed and/or you do not feel comfortable making changes to your website to make it more secure. You may need to contact a professional web developer, to have them secure your website.