Fout, index.php verwijdert... weet niet wat te doen!

Beste, ik heb hulp nodig.
Wilde mijn website van 3.4x updaten naar 3.6, dit ging niet. Ik had admin tools geinstalleerd en wilde mijn database repareren, maar vervolgens deed hij niets meer en kan ik ook niet meer inloggen op mijn administrator.
Mijn webhosting zegt dat index.php is verwijdert... Wat moet ik doen??

Mijn log_error zegt het volgende:(heb zelf alleen vandaag, de 20ste wat gedaan)

[Tue Jul 19 20:23:53 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/robots.txt
[Tue Jul 19 20:23:53 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/error_docs
[Wed Jul 20 01:07:13 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/robots.txt
[Wed Jul 20 01:07:13 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/error_docs
[Wed Jul 20 05:49:48 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/robots.txt
[Wed Jul 20 05:49:48 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/error_docs
[Wed Jul 20 08:42:12 2016] [error] PHP Fatal error: Call to undefined method JToolbarHelper::link() in /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/administrator/components/com_admin/views/sysinfo/view.html.php on line 119
[Wed Jul 20 08:42:20 2016] [error] PHP Fatal error: Call to undefined method JToolbarHelper::link() in /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/administrator/components/com_admin/views/sysinfo/view.html.php on line 119
[Wed Jul 20 09:18:26 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/favicon.ico, referer: http://.../
[Wed Jul 20 09:18:26 2016] [error] [client 62.132.231.121] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/error_docs, referer: http://.../
[Wed Jul 20 09:25:55 2016] [error] [client 91.184.7.3] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/favicon.ico, referer: http://.../administrator/index.php
[Wed Jul 20 09:25:55 2016] [error] [...] File does not exist: /var/www/vhosts/42/127788/webspace/siteapps/joomla-344663/htdocs/error_docs, referer: http://.../administrator/index.php

Wat moet ik doen???

---------- Bericht toegevoegd op 20 juli 2016 om 09:57 ---------- Vorige bericht was op 20 juli 2016 om 09:53 ----------

Krijg als ik nu wil inloggen het volgende:
Error displaying the error page: Invalid JDocument Class: Invalid JDocument Class

Fout, index.php verwijdert... weet niet wat te doen!