Welcome to the forum. I can tell you sound like an intelligent young man, this is a good site to learn from. Dump the guy after the “you blew that call.” He wasn’t talking to his coach. That’s a loser excuse to hope an official takes the bait and lays off. You heard it, and he certainly wasn’t using the correct pronouns to “talk to his own coach/player.” Now, I’m not saying have a quick trigger. But you need to know the 3 Ps - profane, personal, persistent. He went personal. Everyone has their own style of ejection. Use the standard mechanic, be firm, be assertive, and no you don’t have to start the circus with too much on an EJ. But please, bring a little more officiating “umpf” than “you know you can’t still be here after you did that, Coach.” Come on. I think your explanations were good - keep them short, succinct, and don’t try to convince the coach. Tell him what you saw, what the rule is, and move on.