Hi,
The stock is updated based on several things:
- if you have the option "Update the product stock on confirmed status" activated in the HikaShop configuration, the stock will only be updated after the order status is changed from "created" to "confirmed", after the order is paid. But if the order status is not changed because you have a problem with your payment gateway notifications of payment, then it won't happen.
- if that option is turned off, then the stock will be updated when the order is created.
- you want to check the settings of your order statuses in the menu System>Order statuses. If you don't use the standard statuses but custom statuses you created yourself, they need to be properly configured and it can get tricky.