Do you guys think that this is a little harsh or is it perfectly fair?? I think it's bloody spot-on, quite proud of my writing actually!

Dear sir/madam,
Unfortunately your failure to collect the item and failure to satisfy the financial obligations of your purchase has led to a cancellation of this transaction.
I hope you fully understand the reasons as to why this transaction has been cancelled. All obligations upon my behalf were fulfilled with the intent for a speedy collection and payment, you simply did not arrive at the times you said you could, consequently creating more inconveniences.
Furthermore I have issued my address to a complete stranger which is slightly unnerving for my young family.
I would ask you on behalf of the Ebay community to subdue your intentions to purchase spontanaeously without the intention to fulfill obligations as this causes complications for those who have organised to provide such sales.

Feel free to email me concerning the issue at hand.
Kind Regards,
Chris.