I am having a problem with scam emails coming through to an iCloud account which is supposed to be reserved for important emails. All of the spam seems to be coming from the same sender as the style is similar and the headers show the same mail server. It has been relentless and going on for months so I really need to try to find a way to stop these emails.

So far I have tried the following:

• Block the sender. This only works for a period of time until they eventually change the sender address.
• Refrain from clicking the 'unsubscribe' link. I assume this would probably make things worse by confirming that my address is live?
• Mark them all as junk. I thought this would train the MacOS/iOS mail application to recognise them but this doesn't seem to effective?
• Set up a rule on my Mac to block anything where the message ID refers to the particular server where they're all coming from. This seems to work when I'm sitting in front of my Mac, but it's not server based filtering so it doesn't stop the notifications from coming through on my iPhone when I'm away from the Mac. 
• Set up a rule on iCloud.com to try to block the server name - unfortunately iCloud.com doesn't appear to allow this.
• Complained via the DIA spam reporting tool. The sender is probably overseas so I doubt this will help. 

Is there anything else I can do that I haven't already done?