website error fixing (spam mails removing from file)

hi there
i have a similar micro jobs website which has been disabled from the hosting due to a user uploading a spam script.
I have attached the reply below from the hosting company about the problem.
I do not wish to delete and remove all users and their jobs so am looking for some one who can scan the script and remove the spam script, remove the whole micro jobs script from the host before uploading the cleaned script back to the server.

I Think the reply from the host will explain more:

Thanks for taking the time to read this ticket. This site has been disabled as it was found to contain a spam script, which can be used by an external party to send out large volumes of spam emails.

Typically, spam scripts are uploaded by malicious scripts taking advantages of weaknesses in a site's code. Therefore, before we'll be able to re-enable this site, we'll need to know that all malicious scripts have been removed and that the original vulnerability has been fixed. Therefore, you should now:-

- Download a copy of your site, but keep it separate from your clean backups.
- Delete all files from your hosting package.
- Contact us so that we can confirm that all files have been removed and so that we can re-enable the site for you. This will also re-enable access to eXtend.
- Change any passwords relating to the site, including database, administration, FTP, and mailboxes
- Rebuild your site from the latest releases of your CMS, or upload a known clean backup and update all scripts to the latest releases. If your site is custom-built, you should review the HTTP logs and vulnerable source to identify the issue, and resolve it.
- Audit your site's security. Have you removed any installation files, checked directory permissions, removed any un-needed modules?
- Contact us to re-enable the site.

If you require any assistance, please ask - we can, for example, delete all file from your hosting package to avoid having to do this via FTP, and offer advice on security best practice to help keep your site secure in the future.

Best Wishes

Requirements

Help in restoring the website back to original state without losing any files and members.

Skills Required

Wordpress Errors Fix Problems Installation