I keep getting trouble from a Bulgairian IP Address

The IP address is from Bulgaria. I’m not sure if it’s a hacker or what but it’s happened twice and I’ve changed my password already. I have the IP address, but if it is a hacker what else should I do to stop him/her? Or is it possible to use the IP address to email said person and tell them to knock it off?

IP Address: 193.192.56.216