Well, after I created complaint at casino.guru and CC'd in self-exclusion email casinoguru's representative, the magic happened. They blocked me for lifetime, even though they didn't have that amount of time in their "manual self-exclusion".
I like that kind of magic, when casinos change their opinion. Sad, that this casino DON'T CARE about reputation here.
So please tell, what was the problem for their talking head here block me right after he asked me for my nickname in casino?
I can't be sure what's really happening on their back-end, but from what I can conclude from your narrative and the screenshots you provide, you asked live support for self exclusion, some casino might have this method for such request, but apparently they don't, their live support doesn't have the power to process your self exclusion, it must be done through their technical team, of which you were instructed to send your email to.
Your problem here lies on the fact that after their cool-down period, upon being asked if you want to proceed with the self exclusion [and how long], you played for a while. I am not sure which action triggered the expiration of the self exclusion link, the time or that you played, but suppose you proceed with the self exclusion right away, I am sure you'll see and get what LM get; the self-exclusion being processed.
Imagine it this way, you ask for a fast, and your wife or your mother or whoever cook for you, agreed to let you fast for a few hours [or maybe a day], and later on, when they ask if you still want to proceed with your fasting and that they'll wait for your answer in few hours, you took a meal, and only later on come back and said, "hey, I want to proceed with the fast, this time permanently." can they be blamed if they assume you've decided to stop fasting from your previous action?
So yeah, from that perspective, I have to agree that there is no bug from their system.
As for how the magic happen, it's because the representative here [or the one on CG, if they're not the same people] must have a higher authority than the live support that they can issue an exclusion on your account, which probably also the reason why he asked your username.
Ultimately, let's break it further down again. Your issue here is that you feel the casino cheated or will cheat their user because their self-exclusion method doesn't work. Well, it works, if the player asked for self-exclusion and stick to their decision to self-exclude themselves on the entire process, there will be no expired link or the need to restart the whole procedire. So, unless I'm wrong with the narrative and there's another thing that I missed, there is no issue here.