I clicked on something different (to me anyway) a few weeks back, and hadn't realised it was to delay payment till after delivery.. 2 weeks if I remember correctly. One order stayed that way, (much to my annoyance) but I went into my account and deleted the delayed payment bit, I like to pay immediately,  I then received an invoice about 2 weeks later to say my account had been debited for that purchase....perhaps that's what the "unpaid" orders were about?
Also, regarding the seller letting you know....they aren't all like that, I ordered an electronic doorbell weeks ago now, and it didn't arrive. I contacted the seller, and Ebay (without me asking) "opened a case"...and I was told to allow 10 days for the seller to respond...they did...on the 10th day and ebay refunded me! Now THAT I was really annoyed about, because the seller made NO contact with ,me whatsoever, not even an apology.....that's the sort of seller I would complain about.
We have  THE WORKS here........in our local Garden Centre...they sell lots of books and craft stuff and you can very often get really good crafty bargains.