Have you contacted the seller about it? That is usually the first course of action. If pieces indicated in the listing as being included are not in the parcel when it arrives, you can file a 'Not as Described' dispute. The following link explains about that, see Section 4:
http://pages.ebay.ca/help/buy/item-not-received.html
You may be asked to return the whole thing to the seller with Delivery Confirmation, - which can be expensive. If parts are missing the seller ought to refund this return shipping fee to you, but will not be forced to do so.
Alternately the seller may offer to mail you the missing parts, or offer a partial refund so you can buy the missing pieces locally. But you only have 45 days from the day you paid to file, so if you are not happy with the outcome by day 43, you may need to open the dispute.
Also, you have 60 days in which to leave feedback to express your feelings about the transaction.
Best of luck. 🙂
