Blocking a domain name Spam Assassin

Hello,

I've an issue with an spammer and I'm trying to block the domain name @ib.standardbank.co.za on the global blacklist (one per line) on the Spam Assassin configuraion trough iworx.

But copying this line: @ib.standardbank.co.za gives me a warning message that's not a proper value... how can I block an entire domain here?

Thanks!

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