Faction change help please.

Hi my warrior "Amysia" Night elf on stonemaul server cant get a faction change because theirs "A character cannot change factions while there is mail in their mailbox or en route to their mailbox. " but, I deleted all the mail including the one's I red, please help me I don't know what to try or do.
Please reply ASAP this faction change is a limited offer for me :(