Splint3048

I'd like to change my ringtone and I can't seem to get it to change. The instructions say to go into the audio mode the press 0005 the press the call button but all this does is change radio stations. I tried in telephone mode and it made a call to 0005 but got a message that the call could not be connected. anyone know what I'm doing wrong here?

2006 W211 e350