Cadeaubon... are just templates used by your gift certificate products. When a gift certificate product is purchased Cadeaubon is copied. So these should not be published, I have changed them back to templates.
I also went ahead and created a gift certificate order. I received a gift certificate code which I successfully was able to use in another order in your shop. The code f6uwzmSNj was originally published. After using it fully, AwoCoupon automatically unpublished it, since there is no value left in it.
I have noticed that gift certificate the customer purchased that was unpublished on the coupon list, X6zbY53cL, does not exist any more. Did you or any one in your organization delete it?