3. Then we created alt account instead of properly solving the scam accusation against him, yes I know it's so stupid.
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What we can do to have good reputation on BTT?
Why don't you put those two together, and start addressing the scam accusation from your main account?
I doubt you'll recover though, much of your behaviour and actions are very typical for scammers, including the attacks on people who called you out.
Your approach is completely opposite of what it should be: you expect to be trusted, without giving any reason to do so. Why would anyone ever trust you, considering the fact there are enough highly trusted websites out there?