Hi, first of all want to thank the gameflip team for responding + fixing my last suggestion so quickly 
The notifications that sellers get when an order has passed the deadline are a bit weird.
Example: In my listing I set the delivery date to 1 day. The buyer buys the item and I send them a friend request immediately, but they don’t accept/respond for 24 hours. At this point I’ll get a notification saying “Please send the item now to avoid cancellation!”. If I click on this notification however, it brings me to the order page, which now says “The deadline to deliver the item has passed. Do not send the item.”
I feel like the “Please send the item now to avoid cancellation” notification should probably be sent maybe an hour before the deadline to avoid confusion, not at the deadline. You’re getting two opposite messages at the same time.
In this situation I usually just wait for the buyer and deliver the item when it fits their schedule. Very often buyers won’t respond until 2-3 days later and I don’t mind waiting for them. Besides, there’s no “Buyer was unresponsive” option when cancelling an order.
2 weeks ago however, I had a buyer who didn’t respond for 15 days after I tried contacting multiple times. I left the order open in case he was on vacation or something - his profile showed he wasn’t active and it was a cool item. Out of nowhere the order was cancelled either by the buyer or Gameflip, and I got my only negative review. If it was the buyer, it was probably because he was on console and I’m on PC, but even though I asked he never confirmed that.
So a suggestion would be if the buyer is cancelling an order, don’t automatically give the seller a negative review. Just check if the seller responded recently/tried to deliver, and if the buyer was unresponsive. Maybe close the order with no rating in this case. Many others feel this way (1, 2), and it feels like you’re punishing buyers who try to guarantee a fast 1 day delivery. I contacted support about the negative review and the ticket was automatically closed after 10 days.