If you see a user "system - you have been hacked please secure your system" or something of that nature, then yes you were hacked.
Most likely the attacker used the recorder as a bridge to your network. You need to remove that username completely, and make sure to make some password adjustments.
The most important thing for you to do here is make sure "DMZ" is not enabled in your router/modem/firewall. This is how they are gaining access through the telnet port of 23.
DMZ stands for demilitarized zone, it opens up every port available to one device on your network leaving your device vulnerable on the internet. To gain access to your machine remotely you need to have port forwarding done, and remove the DMZ.