Buyer wants a refund on an item not received - but it has only been 8 days

[summitgirl64]

I sold some perfume.  I was told by USPS this could not go out via air because it was flammable.  I shipped ground standard USPS, estimated arrival was for today the 21st.  USPS still shows in transit, I am in Seattle and they are in Florida.  The 2 furthest points in the US.  The buyer has called me a moron, threatened a bad review, and wants a refund while the item is still in transit.  They've said it was almost a month but it's only been 8 days.  Does Ebay really require that I refund while I think I haven't done anything unreasonable? Estimated shipping was 5 days, however it states could take longer depending on the ship from location. 

So now, I have to refund, and I am out $ and product and have to be subjected to be calling a moron? Yes, I am new to selling on Ebay, this is the 4th or 5th item I've sold.  Ready to pull the plug on my entire account buying and selling if this is what I have to deal with.  

Anyone have any advice? What do I do?

Thanks!!!

Kris