^ which app/service did you use?
I haven't ordered stuff online in a while because I've been using Imperfect Foods and just live with eating with whatever options I get from there, but I was using Instacart a while back, and they're pretty good with allowing you to customize your substitution options.
I like ordering from Whole Foods via Amazon Prime Now more, and substitution is more annoying there because they'd just offer something random and ask if you'd accept it. However, I've just messaged the shopper a few times, and even when they didn't communicate back to me they'd actually get what I wanted for me without extra cost. Once I was ordering a small bottle of generic vanilla extract, and they tried to replace it with mint extract
so of course I refused the replacement and messaged them to get some other vanilla extract instead, and I got a $20-bottle of nice vanilla extract for free.