If your website seems to be behaving strangely, it may be that it has been accessed and hacked.
Please regularly back up your website if you fear this may be an issue. With backups, you will be able to restore your site to a clean version, and then fix any potential flaws that would allow hackers in.
There are steps to take to check to see if your site has been hacked.
Look At Your Files
Look over your files either in FTP or in the File Manager and look for a file that is causing the strange behaviour. This may be the index page or the .htaccess file, and you should pay attention to when it was last updated. If that does not match up to the last time you updated a page, it may have been hacked. If there are things in the files that you do not recognise, such as a redirect or a link to a domain name, or code that has been obfuscated, then that means it has been compromised.
Track Down How They Were Changed
When you know what files were compromised when, you can then look through your access logs to see exactly what requests were made. You can access these logs from your eXtend Control Panel under the ‘Log File Download’ page. Older log files will be compressed with GZIP, which you can extract with a zip program.
The log files will be in the common log format for Apache, which you can see here: http://httpd.apache.org/docs/2.4/logs.html#accesslog
Once you’ve found the time the file was changed, you can look through the log to find the first file that was changed, and how it was exploited.
When you restore your backup, you can either update or remove that file, and make certain that your site is protected from that exploit.