Trying to find a player from my shard who systematically attack during everyone else payout

He may not know when your payout is. Maybe he's trying to secure his spot because he's not able to play during the last hour. I wouldn't assume that he is actively trying to sabotage anyone. Also - it's arena. What are you expecting to happen? You get to your rank and then everyone leaves you alone? No one is safe from attack at any time. It's designed that way.