When responding to that email ensure that the unmodified body of that email is included.
edit:
By clicking replay it should automatically attach the previous message
then just replay with something like YES I did request the password change
Blizzard has been having issues with their password recovery system, you may want to visit their site for further assistance
https://us.battle.net/forums/en/bnet/12790219/This post was edited by CYB3R on Mar 27 2017 03:34pm