Assuming Simple Delivery was on your listing you can't change the tracking yourself or mark dispatched. You can try asking ebay but I'm not sure if they're doing that now. You can use callback on here: https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
If not the payment will be held for 14 days. The cost of the unused label will be refunded after 30 days.