I was advertising I was Sniper dueling for items. He hits me up and he wagers a Yeti Smash Taunt, and I wager my Dragon Slayer Dragon's Fury Taunt. Our terms were first to 10 wins. Once I 9-0 him he tries to persuade me into calling it off, despite the agreement we have made. The round eventually restarted and I gave him several chances to redeem himself. None of which came to happen. Sorry if this looks like a jumbled mess.
These are screenshots of the agreement we made and when the duel was cut short due to a round reset. I do have witnesses that can be named upon being asked.