[Help Please] 99kr Issue

Hey all, I am currently using this script for my shops: [Release] [ESX] 99kr-shops,
And I have the issue where I walk into the store select the base items i wish to purchase and as soon as I goto the checkout to purchase the items and it is like the script stops working and everything in the store to add to the shopping cart and the checkout disappears and I am unable to buy any items inside. Any help is very much appreciated.

sup, when i buy one item and i pay the item dulpicate to two. Suppose then i buy 4 burgers i get 8 some one help?

Does anyone know how to avoid having to checkout?