Hi @leet_orange
You can do following things which may help you.
1) Inform your hosting provider to scan your application for any viruses or trojans.
2) Check the Magento files and folders permissions once and set those to recommended one.
3) stop using FTP, use SFTP instead.
4) Do not use Magento default admin url.Use a custom url for the admin panel access.
5) Change all the user names and passwords for the cPanel,FTP (better do not use it).
6) If you worked with some third party for development work on your Magento installation then change all user name and passwords. Also change all the admin access granted to them. Any users created for SOAP and REST api access.
7) Add IP restriction to your Magento admin so that it can be accesses from a particular ip address only.
8) Apply all the patches released by Magento.
Also visit https://magento.com/security check the best practices section there.
Hope all above mentioned points will be helpful for you.