Why can't call+SMS filter block malware numbers?

[anon(9259362)]

call+SMS filter can't block malware numbers

I'm receiving malware SMS on my Lumia 521.
The numbers are 4-digit numbers unlike traditional numbers. (like 9702)
I blocked these numbers from press and hold and block numbers, but they keep appearing on my message list.
How can I block these numbers?

 

[Laura Knotek]

Re: call+SMS filter can't block malware numbers

If you are in the US, please see this link: Spam: Unwanted Text Messages and Email | FCC.gov.