Instacart complaint: Short on fluff

I placed an order for 25 containers of marshmallow fluff that we used to make sandwiches for the homeless. Since we have been making lunches for almost a year now, I try to be as cost-effective as possible when purchasing the ingredients we need. I had carefully calculated the cost of the fluff including the service charge and tip. I am very disappointed that I received only seven containers of fluff because that’s all that was in stock at the store but was still assessed almost $10 in service charges. My per ounce cost was significantly higher than it would’ve been had I received the entire order and could therefore disperse the service charges over a larger quantity. I recognize that sometimes stock might not be available at a specific store, however I believe the remaining 18 jars of fluff should be delivered to me free of any additional service charge when they do become available.