Protocol Question

I had an item listed. A ebayer bought a couple of itmes from me (instant payment and free postage) and requested a third item at a cheaper price as all the items would be posted together. I changed to listing to "For...ebayers name....

Another ebayer has come along and bought the item with instant payment.

Is it unreasonable to request the buyer cancel the transaction?

Do I have the right to cancel the transaction and refund the money as it quite clearly states that it was for a specific ebayer?

Advice appreciated.