How to remove malware affecting indexing on Dawn theme?

[maeson-shop]

Hi there,

After activating Google Search Console, I took a closer look over all the pages, which weren't being indexed properly.

Here, I stumbled over the following situation, which I suspect to be malware:

• 8 pages which are being "blocked by robots.txt-file"
• the pages are all /collections/vendors...
• A) they all initially seem to be linking to an incomplete /about us page (banner image missing), which I can't locate in my CMS/frontend
• B) after a while, they seem to be dead-ending automatically and link to a 404 page
• the page titles of a/b display varying spam messages (crypto coin / madden coin ads) - see screenshot
  

So they appear to be creating themselves with different messages/spam content and turn 404 after while.

See the screenshot of my Search Console here:

See screenshot of page link leads to:

Does this look familiar to anyone? How do I get rid of it?

http://maeson.shop

Thanks in advance!