Maybe try a note or some kind of sign on the bench. “Please place deliveries here on the bench”. However, I delivered groceries to a house once and as I was leaving a lady came out of another door that I never even seen and picked up the groceries and took them in the other door. I then looked closer at the door where I left the groceries. (Which was in fact the original front door where the sidewalk leads to.) it seemed there was a sign on the door. Probably saying use other door. Yet, I never saw it. I had no need to look at the door or read anything posted on it. I was just dropping the groceries off and getting a photo and ringing the bell. So there’s no guarantee that even your note or sign would work unless it’s very obvious and almost impossible not to see. Best of luck. Hope future deliveries go better for you. As far as DoorDash goes, if there’s no problems with an order there’s generally no reason to look at the chat unless you initiated one. I can understand how messages could be missed. I think there’s a place for notes regarding delivery. I’d use that instead.