Hi Delita,
There are 2 things that can be happening here.
First, for some players the realms lists are displaying in a different order so that it appears that the realm no longer exists, or they may not be showing the number of characters on the realm once it is found in the list.
In these cases, re-ordering the realm list (click the realm name “tab” at the top of the column) should sort the list back into an order so you can find the realm. From there, even if it looks like there are no characters on the realm, once you login to the realm you should find your characters on the character select screen.
Second, as Anessa reports, it appears that characters may be “deleted”, as in - they’re not on the character selection screen either.
To everyone here, if you can first check the first “solution” to see if this helps find your realm and character, that would be great! Otherwise can you please report back with the name and realm of the characters affected.
@Anessa - this is being investigated, but for now we don’t have further information
Thanks!