Can't access login page - malware on site

Hi. So this is going to be a bit long winded.

I had asked my host provider to help me with something on my site, and they responded saying that "Removing malicious links from a database has a lot of risk involved and is outside of our scope of support. A quick search through the database shows me that for alone there are about 5000 references in the database."

I had a look at the page source on my homepage and found the link twice within the coding.

So firstly I tried to follow these steps:

Wordfence came up with a few lines that didn't seem to be doing anything and I resolved those but it had nothing to do with the malware.

So I then tried following these steps:

It then wouldn't let me log back in and wanted me to reinstall Wordpress. I tried that and everything was gone. It was just the standard theme with the 'hello world!' post.

I used FTP to restore the files from my previous backup, so it's back to how it was. Still with the malware popping up. But now I cannot access the login page to get into Wordpress. It comes up saying:

Fatal error: Cannot redeclare register_setting() (previously declared in /wp-includes/option.php:1871) in /includes/plugin.php on line 1788

Can anyone help me please? I have been redirecting my website to my Facebook page just so any visitors had something of mine to go to. I have turned this off for now. You can see my site here:

Any help would be really really appreciated! Thank you.