Angry buyer

I received this message less than 12 hours after dispatching an item (not due to be delivered for 9 days) nearly 2 weeks ago
‘I have been told this item was dispatched on Wednesday by ur tracking but amazon are telling me it hasn’t been dispatched yet but if it was at a Manchester Post office how come it is going to take over a week to get to me and I don’t understand the refund or replacement part written on the tracking , I was hoping to be able to use this item as an Xmas present , what the hell is going on ???’
Then he messaged me on average twice a day, asking for a refund, even sending me a selfie (yes a selfie). Of course, I answered politely all his emails. His item was one of the few items that actually arrived on time. Today, he left me a very nasty feedback telling people to avoid buying off me, etc, etc. The 1st negative or even neutral in 17 months. His problem no doubt was that he was angry that a £10.00 item was sent tracked. Unfortunately for him, I would sooner stick drawing pins in my eyes than give items away free to blackmailers.