Instruct: Classify Amazon reviews into positive or negative sentiment
Query: My first disappointment with a vendor

I could understand if an item was out of stock...as long as I'm informed of that. But my order was for a set of 4 and only one piece was sent...no explanation. When I went back to Amazon to see if I ordered the correct item, the item description said that it was out of stock and availability not known. Customer service at its worst.As far as Amazon goes, I have to give their customer service props for the prompt refund and paid return address label...customer service at its best.