Curbside order adjusted- but there's plenty of inventory on the shelf

I did a curbside order after seeing in store that an item cost less on the app. I had to add other items to get to the $10.00 mark. It took around 25 minutes and when I picked it up, they claimed they didn't have enough inventory. I was just in there and saw they had it on the shelf and on an end cap. This has happened twice so I'll be doing orders at other stores in the future. I just don't understand why when I already saw they had plenty in the store to lie about it.