Screenshots of correspondence is good of course, but this is no evidence at all.It's easy go to telegram, on the channel or group click on the drop down menu and click report. You have option to state why you are reporting the group or channel in the case what is states is not your reason. Also note that there must be 30% of the whole members of the channel reporting for the channel or group to be labeled a scam channel or group.
Secondly you need to also know you can screenshot correspondence with the owner of the group or channel with proofs that truly funds exchanged was done between yourself and the owner of the group or channel that way forex Peace Army can look at it and take the necessary action.
The scammer knows you can take screenshots of correspondence and he can write anything and introduce yourself as anyone.