bad robots.txt virtual

I have a huge problem for some time, a bad plugin put me a virtual robots.txt;

User-agent: *
Crawl-delay: 10

and I can not destroy this.

I had put a physical robots.txt, but the result is nil because Google continues not to reference me.

I just try your plugin, (another before) and nothing changes. I register your

but my files still indicate

User-agent: *
Crawl-delay: 10

what can i do more ?

tks
https://www.artisanathai.com/