I'd reply saying that you've booked the day off, as requested, and would like 250 euros paid into your paypal account to compensate for loss of earnings
Couldn't get the handle out of my head so I checked his profile. I sold him some NOS Control Tech V brakes a month or so ago. PMs were curt, but not rude. I sent them to a friend of his in the US (next day after payment) as I couldn't send them to Prague with tracking at a reasonable cost. Checked the tracking online and they arrived in 4 days. No feedback. No "thanks, they arrived" PM.
Tell him to stuff it up his arse. Sideways. Maybe a flite's too small for that, try a BSO style gel behemoth. In fact send him one of those; that'd be funny.