You can't expect everyone to get along in a server with hundreds of active players. Here's all the steps you can take if you're having issues with a player, and what to do if you have been blocked.
Be nice to others. Players typically block you if you've said or done something to hurt them. If this has happened, you should respect their wishes and stop trying to get in contact with them. Trying to communicate with someone to ask them why they blocked you typically only worsens the problem and could put you in a deeper hole. If you just let it be, the player will likely realize that they have nothing to gain from blocking you and they will eventually unblock you.
Blocking Someone In Minecraft
You can ignore players with the command /ignore. This will stop the player from sending you direct messages and teleport requests. This will also prevent you from seeing their messages in global chat.
You can use the command /dynmap hide to hide your location on the Dynmap.
You can ban a player from your claim with the command /setclaimflag noenterplayer.
Blocking Someone On Discord
You can block a player by right clicking the player's name and selecting the block option. This will prevent you from recieving direct messages from the player and will hide their messages in any mutual server you are in
Turn off Direct Messages
For all shared servers that you are in, go to your server settings, find privacy settings, and turn off direct messages.
Right click on a player in a voice chat and turn their user volume down to 0%.
For extreme cases, you can report the player through https://dis.gd/report.
Reporting to Piglin
If you have taken all of the appropriate steps and the user continues to harass you, create a ticket on our Discord server explaining what happened. Screenshots, audio recordings, and other forms of evidence will help. You can recover logs from ingame chat using the steps provided here. Show that you have asked the player multiple times to stop communicating with you and that they continued through that. In the evidence, also explain what they said and how their actions breaks Piglin's rules.