robots.txt problem that is hampering my seo immensely

Halo Warriors, i am having this peculiar problem with my wordpress website property.regrob.com . Earlier my pages were ranking in google serp very nicely but suddenly the pages started disappearing. On close check of pages i found links to gaming sites were injected in my pages and i manually deleted those. But the pages are not coming back.

The google webmaster is showing alien content in my robots.txt file —

Line 18: phentermine pill cod Syntax not understood Line 19: phentermine by prescription Syntax not understood Line 20: phentermine price online
where as my robots.txt file is showing –
https://www.property.regrob.com/robots.txt

and in my settings i’ve saved my robots file as just –
User-agent: * Disallow: /wp-admin/ Disallow: /wp-includes/

Now what is the solution to clean my robots file and bring my pages
back in serp. Any help is appreciated.