Open Mail on a Mac, right click over "no sender" to see the actual email address and then make a Mail "rule" to send any email from that sender directly to junk/trash. In short, do your SPAM management yourself
on your Mac and it will then deal with it on your iPhone too.
I have a rule in Mail, File, Preferences, Rules with MANY entries to basically filter my own recurring SPAM. It's quite easy to add new ones to filter with the rule. It would even be possible to make one that filters all mail with "FROM NO SENDER" but I would right click and see what the underlying email looks like (if one will show). If some of that email address is always the same and you know you would never want email from that source, you can make your rule purely filter that chunk to JUNK.
For example, suppose the right click under NO SENDER shows an email address like <unique something>@welovetospam.com You check the next one and the part before the @ is different but the part after is the same. You could make your rule like this...
In the future, when ANYTHING arrives from that URL, it is going to get auto-moved to your Junk folder, not showing in inbox for your Mac or iPhone.
If the bad guys alter the part after the @ a bit (and some will), just hover over the new URL, get on the rules screen, click the + in the circle next to the existing one and a new From:Contains @ <new URL you want to filter> will appear. Click OK and now your rule will filter for
both URLs.
Besides "No Sender" another common line from the 2 you show in the post is "BEAT THE HEAT: Portable AC" If that is consistent in all such messages but FROM is regularly changing (or the part after @ is a mainstream thing like @gmail.com and you don't want to block any friends that might use @gmail.com), you could switch FROM to "MESSAGE BODY" and then put those words in the box. Then any email that includes that line would be redirected to junk.
The name of the rules game is to find some common content for all email you want to automatically junk that is unlikely to be content that would be associated with anyone from which you DO want to receive email... and then use that "definitely JUNK" content as the basis for your filtering rule entry: from, subject, message body, etc.
My rule like this currently has about 80 entries in it and I just about do NOT get any undesirable SPAM in my inbox. However, if a new one does arrive, it's easy to add
another entry to my RULES list to stop it from showing again.
Another tip: have a main email addresses you use for main contacts and then 1+ less important email addresses (plenty of freebie options like gmail for this) you use when you need to share an email that seems like it COULD lead to spam. The less important ones can simply be jettisoned if one starts getting too much SPAM, replaced with a new one for less important situations that need an email address. Save the main one for friends/family/etc: trustworthy contacts unlikely to SPAM you.
Using one email address for everything- as many people are prone to do- guarantees that a lot of SPAM is going to come to that address. Rules can help deal with all that but that ability to easily dump an email address used for less important connections is a great way to cut out a lot of SPAM in one "delete."
It's been a while, but last time I checked, Comcast will let an individual set up at least about 5 email addresses to use. One main one and 4 to create, use for lessor/questionable contacts, then delete and re-create if too much spam starts coming to address #2-5.
