content is gone

Hi there folks.

for some amount of time i hade trouble log onto my site.
Some error is the config.php caused the problem.
the line looked like this in the browser.

Fatal error: Call to undefined function wp_raise_memory_limit() in /storage/content/04/143004/wilmermedia.se/public_html/wp-admin/admin.php on line 141

So i got a reply of the first topic i had and he wrote like this.

Try downloading WordPress again, access your server via SFTP or FTP, or a file manager in your hosting account’s control panel, and delete then replace your copies of everything on the server except the wp-config.php file and the /wp-content/ directory with fresh copies from the download. This will effectively replace all of your core files without damaging your content and settings.

Some uploaders tend to be unreliable when overwriting files, so don’t forget to delete the original files before replacing them.

and…

You’ll start by downloading WordPress again from https://wordpress.org/download/

Then, on your installation, you’ll delete everything on the server except the wp-config.php file and the /wp-content/ directory as it correlates to the copy of WordPress you just downloaded.

Then, where the installation was, upload everything from the fresh WordPress download except the wp-config.php file and the /wp-content/ directory.

So i saved a copy of config.php and the whole content of /wp-content to a SSD-drive locally.

What i did was to upload succesfully from my domain-admin control panel and i could log on. But i cant use the old config.php file and the error ive got is.

an error occurred while access the database

When i upload the wp-content all the files and plugin was back but its like i´ve just upload the plugin and themes.

What is the solution here? did i miss something?