Do I understand the chronological narrative was that you contacted live support and ask for self exclusion, which they redirect you to email the support team with such request, they then issued you a 24 hours cool-down, of which after the cool-down, you can extend the period to permanently [or any other time you preferred] if the request is submitted within certain period after the email asking about this to you was sent, so you play there for a while before re-visiting the email and try to request the permanent self-exclusion, which no longer works?
Just like when you request a password reset or a 2FA code over email, the link won't be available forever. Depending on what it is you are requesting, it could be available for 10 minutes, an hour, a whole day, or any other time period the service sets. When that time expires, you can't revisit the old link anymore, and you have to request a new one.
Exactly, OP's complaint here is that the casino being irresponsible by not allowing a self-exclusion, with a supporting evidence that
the link is invalid, argued that the casino tries to scam their customer by making this self-exclusion impossible, that he
can't self exclude after he won. But if what happened here is that he can't self-exclude after a cool-down period because he played right after that cool-down period is over, or that the link expires because he played, it's not an issue at all, it's a stupidity. LM tried the self-exclusion himself and it worked smoothly. No scam happens here, and this thread is nothing but... well... stupidity.