I'd give it a little longer, it may yet arrive. The estimated delivery date is just that - an estimate.
One day after the estimated delivery date you can open an eBay item not received claim to get a full refund:
https://www.ebay.co.uk/help/buying/returns-items-not-received-refunds-buyers/get-help-item-hasnt-arr...
That seller has an awful lots of negs, they won't be trading for much longer, that's for sure. Your money is protected though.
