How would one go about blocking a relay? 
Like the ones ReplyGuy uses.
#AskNostr relay.wellorder.net 

 I wasn't asking you! 

 Depending on the app you use. But you don't really block, you just don't connect to them. 

 You should check your account settings < relays < and delete those that are linked to that spam, and you can block or mute those accounts later 
https://m.primal.net/Kqhl.jpg