According to one my delivery men, if your chosen product is out of stock the pickers are automatically sent a "suggested substitution" (via some weird algorithm I assume) which they have to use regardless of whether the actual picker can find a more suitable one.
I suppose it explains why they thought I should use snack size chorizo to stuff my turkey when they didn't have any fresh stuffing. I would have thought even a pack of stuffing mix would have been preferable, but apparently not.
I do accept you're a bit in the lap of the gods with food delivery but their choices do baffle me at times!