Am I being lied to?

I won two auctions on July 22nd and paid that day, immediately upon winning. A week later I realized they still weren't marked as shipped and the auction stated they ship within two business days.

I emailed the seller asking about it. He messaged me back a day later saying that he went to the post office and the package sat there for a week because of insufficient postage.

He claimed he would give me a refund for waiting and that he shipped it.

It has been one day, no refund, and he showed only shipping one of the boxes. I messaged him again today about the second auction and he didn't respond, but listed it as shipped.

Tracking shows that the one item was picked up and processed yesterday. Is he lying about even shipping it the first time? Shouldn't he have marked it shipped a long time ago if he had? How can I prove he waited a week and a half to ship when it finally arrives?

Also, is this situation enough to leave negative feedback and demand a partial refund? He did mention a refund, so he's now obligated, correct?