Asking for advice

okay, so here's the thing. I feel I didn't do anything wrong here, and I'm feeling too lazy to want to correct someone else's mistake. But I don't know if it's the right thing....

let me explain, and you can help me out.

A few weeks ago, I ordered some scrapbooking things from Joann.com. The estimated time of delivery was 5-10 business days. A little over a week later, I got a BIG box from them, way bigger than needed for all 4 items. Inside were only 2 of the 4 things I ordered. Looking over the box, I noticed that one end was taped with that tape that has strings going through it, so is really secure, but the other side was taped with a single layer of basic packing tape, and had ripped at one end, leaving a hole about 4 inches wide. I hadn't seen the two things that were missing in person, and figured the hole was probably big enough for both of them to fall through.
However, and this is important, I realized that items are not always shipped in the same box. So I checked the packing slip, and ALL FOUR items were listed as being in that shipment.

So I called Joann's and told them that I had received the box, but two of the items were missing. They looked up my order, apologized, and assured me that they would send out replacement items. I said thank you, and asked for an estimated date of arrival. Again, they said 5-10 business days. I said that was fine, thanks again, and that was that.

About 5 days later (so sooner than the first time, but within their estimate), a package came with the two items. I noticed that one of them was maybe a bit big to have fit through the ripped hole in the first package, but figured I was wrong. I was happy, and went about my business.

Then TODAY, about 5 days after the SECOND box had come, so about 10 days after I called them, ANOTHER package arrived, with the two items again.

So what I guess happened was that the two items had never been in the first package, but had been shipped separately. So here's my problem. I have two things I did not pay for. BUT I did check the slip, and it said all four things should have been in the first shipment. AND when I called, shouldn't it have been in the system that the items were in a different shipment? Oh, and I had also received an email before I got any packages saying that my initial order had been shipped, and it listed all four items, and said nothing about multiple shipments.

I really don't feel like calling them up, and asking for a return slip (cause I am not paying to ship it back to them) then re-packaging them up and driving to the post office (out of my way for anywhere I go) and sending it off. I don't feel it was my mistake.

What do you think?