An accusation with Telegram screenshots is too weak. Deal with forum PM so there will be strong evidence if someone tries to scam you. We can't judge anything based on telegram chat history. It would be edited or impersonated. Someone easily could create a fake chat history about me or could create a similar username. If @ses-store threaten you on forum PM then we would able to punish him/her. Otherwise, it's not reasonable to punish someone on the forum due to Telegram chat.

By the way, always try to use forum trusted escrow when you are going to deal with someone even forum users. So you might avoid unwanted scam attempts.