How to restore old character names after account reactivation

I've been inactive in WoW for several years. I just renewed my subscription to find that all my character names have been mangled. Presumably, this was done by Blizzard to free up the names for other players that might want to use them.

I would like to restore the old names. To the best of my knowledge, the names I used to use are still available on the realms I used to play in.

I understand Blizzard provides a paid name change service, but I have some fifteen characters on my old account, and that's a substantial amount of money. Are there any other options for returning players?

If a character's name has been changed by Blizzard - for violating naming policies, due to inactivity, or because it became a duplicate due to server transfers or undeletion - you will be prompted to enter a new name when you try to log into that character. If their old name is available, you can reclaim it; if it isn't, you will need to pick another one.