Dash food service - buyer does not communicate with you when making a substitution

I used the Woolworths Dash Food Delivery. I selected the option that the shopper needs to communicate with me if the item is not in stock for a substitution. One of the items I ordered was a cheesecake. The buyer replaced it with a chocolate sundae without communicating to me. Very unhappy with this service. I will not be using this service again. I never had this issue with Checkers.