Btw, one forum user made us an offer to which we agreed and for which we paid (the offer included a half-year placement of a banner). But two months later, the banner was removed from the website and the user stopped communicating. The question is - could this be the reason for creating the flag?
Yes, I think that's a reason for a flag. In any case, I would first write an accusation on this board, with all the evidence (write down e-mail or messenger messages with pictures and the exact course of the scam): Bitcoin Forum > Economy > Trading Discussion > Scam Accusations. If these clearly prove the case, a flag can be created and assistance asked for in this thread. I wish you success. 