Sorry if this has been answered, but I've searched the forum and cannot find an answer.
I have my site setup so I cannot go into negative inventory. I have tested it and it works. The problem is when you have multiple users checking out at the same time you can go negative. When I set the stock of my product to '1' I tested buying one product 2 times and was denied the second time...which is how it is supposed to work.
I reset the stock level to 1, called a friend and we both ordered the same product and both of our orders were confirmed! I go back into my admin panel and I see my stock at -1. This is not possible.
The reason this is an issue is because my site is going to sell a specific amount of product for a specific period of time. So if I have 50 available and 100 people try to buy it all at once, then I will have to refund 50 customers because opencart allowed 50 additional users to checkout. The process only works if a customer confirms their order in their shopping cart, then it subtracts from stock.
I have my setting correct, I know this because I have tested it with just me trying to checkout 2 items when only 1 is left.