When you see messages like "I received it, thanks admin," it's a clear sign to run away and never look for that kind of thing again.
One word - 'Scam.'
I've seen this countless times in these types of Telegram groups.
About 90% of the "people" in these groups are bots.
Other bots are constantly spam inviting the remaining 10% of real users daily.
And so it goes in circles. 99.99% of real people eventually realize what's happening and leave/report the group immediately, but unfortunately, there's always that 0.01% who don't.
Unfortunately, by the time someone realizes what's going on, it's usually too late.