There's a database amnesia going about. On 13.9.2018, or thereabouts,
resident of Kalimdor went hideously missing in the realm of Nighthaven.
In the general area of Hinterlands, locals remember the fishy priest
well. Rieblin posessed average riding skill and was well trained
in cooking and alchemy so it is questionable that lack of content
got to her.
If you have any observations regarding the incident, be sure to
consult your nearest pigeon hole in the speediest manner.
Follow up: Is it a known bug that undeleted character is unable to receive any mail after the operation? That seems to be the issue now. Received mail disappears into void nor can other characters send mail to her. The undeleted character can send mail though, just incapable of receiving any it seems.