Question about sketchy/spam texts coming from the official facebook number

A few months ago i was receiving obvious phishing texts saying my name, "you have 4 new facebook notifications" followed by a facebook link and a bunch of emojis. The strange thing is these texts were coming from the 32665 number that sends verification codes for insta and facebook. I ended up blocking the number and a few mins later I got a notification about an unrecognized fb login request on whatsapp. I changed my password and that seemed to be the end of it. The thing is, I still have that number blocked and as a result, I dont recieve verification codes for 2fa. Is there any risk to unblocking the number?

Also, does anyone know how they would have known I blocked the number? I assume blocking the number triggered something because the login attempt happened just minutes after blocking the 32665 number.