You do not need to contact eBay
It would have shown you an estimated delivery date on the listing, before you purchased
Firstly, contact the seller and ask
If they are not helpful, or tell you nonsense
Open and follow through with the item not received dispute if it is overdue
Other members cannot tell you when it is due
What is the item number (not the order number)
Where is the seller registered?
This is not something you need to contact eBay about, you have all the information
Otherwise, did you purchase as a guest?