New Ways to Get Backlink

I received an email like this today and I replied to it using my dummy email saying that their client website will be de-indexed and will get penalized by SE because I will do Black SEO to their client website and make sure he could not fix it whatever technique he will do as an SEO... HAHHAHHAHAHA

We got the same message to one of our sites. I hope nobody falls for this and gives him a backlink.