Car on Ebay Auctions/Sales

Hello, I’m auctioning my car on Ebay. Defect. Wanted to cancel my car today but completely different times at the office today. Tomorrow, I don’t know. Never deal with Sylvester. Had to work today until 16 o’clock. Shit. Auction ends on Saturday. How do I proceed now? With the unsubscribe. I can unsubscribe the earliest Wednesday afternoon. Must I make an extra contract to be sure? If the buyer says he’s canceling it.? I really don’t have a plan.