Themegrill'e yazdım cevap geldi. TG Demo Importer eklentisini kullanmıyorsanız silin yada son sürüme güncelleyin.

Firstly, we are extremely sorry that you had to face the problem in your site. It might have caused by TG Demo Importer plugin, not the theme. The hackers seem to use its vulnerability to reset the site.

So, there are certain things you can do to get back your site. Firstly, if you've kept backup for your site, you can restore your site using it. Otherwise, your hosting provider might have backup of your site so, please contact your hosting provider asking to restore your site to the recent backup of the working site.

Also, we recommend you to remove the plugin if you do not use it anymore or update to the latest version if you still need to use it.

Again, we're extremely sorry for the inconvenience caused.