You won't find your order by signing into your account if you checked out as a guest, and there is no way to track it.
The email you got from Ebay when you bought the item will give a range of estimated delivery dates. This will have been sent to the personal email address you supplied at checkout.
If the latest estimated delivery date has passed, you will need to follow the usual 'item not received' process.
All the details are here:
https://www.ebay.co.uk/help/buying/returns-items-not-received-refunds-buyers/returning-item/returnin...
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)