Pre-Order Character Slot
They are sent out in batches. You should receive it by the end of the week.
https://help.guildwars2.com/entries/94582027-Heart-of-Thorns-Pre-Purchase-FAQ
Eligible accounts that are upgraded with a pre-purchase serial code after July 10 will receive their slots on a weekly basis after that.
The Burninator
Pre-orders get no bonuses. Pre-purchases do. I hope you meant pre-purchased Heart of Thorns. =)
Some purchasers have stated that the bonus character slot took about 10 days to arrive, so be patient.
Good luck.