Hi there Frinntintin,
Thanks for reaching out about entering your inventory. QuickBooks Desktop is a great tool able to help you keep track of sales and purchases of inventory so you know how many you have on hand. I can point you in the right direction for assistance with entering these transactions properly.
In order to know how you should be entering this into your inventory, and if any modifications are needed to be done on the prior credit card payment, I recommend reaching out to your accountant. They'll be able to view the entries already done in order to assist in making sure all affects your books correctly. You can find an accountant that has experience using QuickBooks software near you by checking out our Find an Accountant page.
If you have any other questions, feel free to reach out here.