Golem Banker bug
I’m not sure where you see it says on your consumable that you get one for each new Alt. You don’t.
The one that is generated for newly created characters is a bonus from DDE or CE versions of the game, only.
The one purchased from the Gem Store is a 14-day Account-bound one-item consumable.
In the future, carefully read the description on the item in the Gem Store.
Or, if you use the Wiki, make sure to read any Notes.
The golem banker sold seperately from the deluxe upgrade will be emailed only once to the character that made the purchase, it will not be available to newly made characters via mail (via bank).
http://wiki.guildwars2.com/wiki/Golem_Banker_%28consumable%29
There is more than one type of golem banker.
The one you bought is probably this one: http://wiki.guildwars2.com/wiki/Banker_Golem_
It’s 500 gems, account bound and reusable. You get only one per purchase.
What you may be confusing it with is the golem banker from the digital deluxe upgrade. 
http://wiki.guildwars2.com/wiki/Digital_Deluxe_Upgrade
That upgrade is 2000 gems. With it, every new character gets a golem banker which is soulbound, reusable and lasts 2 weeks.