Scuse for my bad english

I have to create X coupon to deliver to X customers. Coupons set to zero the price of the product.
To do this i follow this step:
1.create an unpublished template coupon within hikashop/discounts/coupons. The template (configured like the above image) have "quota" and "quota per user" set to 1
2. i create a coupon generator plugin that use the template like id coupon ( and specific serial format)
3. i create a pack using the coupon generator created at point 2
4. from pack i generate the X coupon
Now...i try to use this coupon.
I try to login with a test user, add on the cart a product using one of the coupon: the price is correctly set to zero. The user can procede to have the product for free.
At the end, the user receive the confirmation order on his email.
Here the issue: the user receive the confirmation email order containing a new coupon id (different from the one used for the purchase)- In this way the user could receive 2 free coupon: one received from me and one created from hikashop and report on the confermation email order.
Infact on hikashop/discounts/coupons i found the coupon that i generate that result used, and a new generated coupon that result usable. I don't want that this second coupon is generated.
How can i do?
I hope that now my issue is more clear
Regards,
Rob