Are you trying to block the email domain that you see in the address bar or have you checked the headers of the emails to see what the name of the actual name that is sending the emails is?
If you have not checked the headers there is a good chance that you are not blocking the correct domain.
Spammers generally "spoof" the email addresses and domains in an attempt to beat the spam filters.
If you have not checked the headers to find the true domain you need to log onto your email account using a web browser and then tick the box to the left of the spam email and then click on "More" in the menu bar then "View Source".
This will show you the full details of the emails journey to your Inbox. This will show you the email address that sent the email.
It is that domain that you need to block but you will most likely find that a waste of time because as you have found the spammers constantly change their domains and email addresses.
You may find that setting up a "Rule" to discard the spam with something relevant to the spam that you are receiving will work.
