Those dates are only eBay's estimates for delivery not a guaranteed date so worth waiting for Monday's post,  and if it doesn't arrive by then ,  go right of the item purchased,  and from More Actions select....  I Have Not Received My Item.

If you are not fully refunded within 3 days,  you must escalate the case on day 4 or within 30 days from opening the case,  and eBay will step in and force the refund.

Do not close the case early for any excuse or promise the seller may give,  and do not forget to escalate.

@ashrafz_78 

The estimated delivery dates  given by eBay can be quite inaccurate at times.  If you click on the tracking number on your order you will be able to see when Royal Mail or the courier received the package.  From this you will be able to work out for yourself roughly when it should arrive. You should also be able to see where it is and if a specific delay has been recorded.  It is not uncommon for items to get delayed in transit particularly after a bank holiday period due to increased parcel volumes. If your item was being sent on a Royal Mail untracked service the item is very likely still in transit. In the first instance if it doesn't arrive within a reasonable timeframe contact the seller.  The vast majority of sellers are honest, decent people and will deal with the issue sensibly, particularly if they are UK based business sellers.  If the seller does not respond then you will need to open an Item not Received case.