Seller order cancellation form should provide space for explanation to buyer.

[psloter143ul]

I found that my item was missing parts when packing, therefore I proceeded to cancel order.  However, there was not where on the form to provide the buyer with a more detailed explanation.  They in turn left negative feedback.  There shouldn't be a need to contact the buyer first and then cancel an order that can't be fulfilled.  A seller shouldn't receive negative feedback for taking the right action and the seller got a full refund.

[slati_2013]

It is the seller's job to make sure all the parts are there before they put the item up for auction. Most buyers will assume the seller canceled because the seller failed to sell it for a higher amount. You should contact the buyer and explain why you want to cancel the transaction. The buyer might even tell you to send it anyway with the parts missing. You have a far better chance of not getting a negative by discussing it with the buyer than just canceling. 

[dhbookds]

there was not where on the form to provide the buyer with a more detailed explanation.

so why not email the buyer, as said above, before you cancel it?.......seems like common courtesy to me...........

[*eponymous*]

A buyer who does not get the item is an unhappy buyer who might/may/will leave ebay, thereby depriving other ebay sellers the opportunity for sales. That affects ebay, you, other sellers, and buyers. That is why you get a defect for cancelling without a request from the buyer.

Let the buyer know your circumstance, offer a discount, and give the buyer the option to get the item, as well as the option to cancel. If the buyer agrees to either option, you avoid the defect and the neg...and you have a happy buyer, happy you, etc.

[sg51]

What I do in such a case is to both ship and refund in full, with an explanation message to buyer.

No neg.

No ebay strike.