Nostr is a protocol, not a platform. There is no central authority to remove people from a protocol. Blocking is your only option. Even the creators of apps that use the protocol can’t keep people from using the protocol.
Discussion
Actually, contrarian — blocking is NOT the ONLY option. You’ve clearly missed the memo.
Good luck.
Why escalate a situation when blocking is available? Why do you feel you have the right to make decisions on who others can communicate with?