This does not happen only in your group it even happened on a reputable exchange telegram group but you have to try your best and ban user reported for scamming because ever since the cryptocurrency was acknowledged as an innovative technology to make people financial freedom a lot of scammers have seized the opportunity to target newbie crypto participants or user that have urgent issue to scam them off their fund.
Easy to say to try your best but have you read the OP?
If don't read what the OP said how would I know what the issue is all about?
it says there that thousands are coming in and the bot is already doing its best which means that the anti-spam that was in place is not an effective tool.
The tools can't be effective because 95% of all scammer on telegram usually act as an imposter using the admin name and if the OP could not check their follower list and remove the imposter
What the imposter usually does is wait for a newbie member that had an issue, send her a pm.
Yes, these spams are used to promote scams but I don't think an average Joe that knows how to think and has a common sense wouldn't really fall for that because it is an obvious scam.
If you understand how this I posted scammer operated you know newbie investors will always be their victim and it something I have once experienced when I join crypto.