Can I text a number that I added to my spam list?

[AC Question]

I had to add an ex that would not stop texting me to my spam number list. It worked because when I go to my 'spam messages' I can see all of the texts he has sent that I did not get notified for. I can only see them when I purposely look for them. If I was to go to my messages and start to write a new message to that same number I have on my spam list, will it get sent? Or will it not be sent because that number is flagged. Basically, does the spam list work both ways, or only for incoming messages from the blocked number?