Aduvar

seems unfortunate, i suggest you use the ignore system that is ingame

Have you checked if you are using any postal Addons to send mail? also have you tried deleting WDB?

Is it just the guild messeges you send that won't show up? try checking your chat options which can be found if you right click the selective chat bar ontop of your chat (like in the picture linked) make sure all the settings are correct