how to block/disable "Class 0 Message"

i've been getting a spam "Class 0 Message" from a certain number (not my network provider) and it keeps on popping up with the same message "good day!" every 2 or 3 mins for the past hour! it's getting annoying. i tried marking the number as spam, and disabling notifications and cellular broadcast but it's still there. is there anyway i can disable this class 0 message? please help

thanks

If there’s a message icon then tap it and tap settings > cell broadcast settings and deselect.