Hi,
Make sure that the "clean cart when order is" setting is set to "created" in the HikaShop configuration.
Also, if you have the "Enable multi carts" setting activated in the HikaShop configuration, it's possible that you got several carts with the same content if you made several tests. And thus, if you checkout and it removes the current cart at the end, you might just see the previous cart thinking it's the same one that wasn't deleted.
So try to clear all the carts of your tests in Customers>Carts and try again.
