Negative Feedback and Hostile Buyer

[suzcarl]

I am stressed out!

I sold a buyer a pair of NWT 24 month baby jeans, with original paper tag clearly attached, and bodysuit in like new condition. There was no word from the buyer until three weeks after receiving the items, she left negative feedback, saying the items were "worn and not new". 

Ebay suggested I write the person a message to find out if perhaps that feedback  was meant for someone else.  I even composed my message to the buyer with an eBay representative's help.

The buyer then emailed back that the items were "worn for years" and that my message was "nonsense talk".  She threatened to contact eBay about my "terrible message"! 

After dealing with this, I'm feeling as though it's not worth selling on eBay.  My feedback was 100% positive on over 1,000 items before. How do other buyers cope with situations like this?