The reason they don’t tell you what you typed is because they know someone will use that information to figure out who reported them, or at the very least narrow it down.

Make sure to stay cordial in chat - you will never receive a report if all you say is “gg! tyfp” or “oops, my bad” or language such as “please remember…” “can you please do X next time?”

There’s likely going to be someone who will respond to this thread telling you to never speak in game. Don’t listen to them. It’s very hard to get a report - just make sure not to curse and not to vocalize anger at another player, and you’ll be fine.