Are you saying that the products still have their prices, but that the total is $0? That is very strange. Each time you update the order, it goes through each product and adds up your total. So, that is why your order total is most likely getting changed. What I don't understand is why you are getting $0. If your products have a price, your order total should have a price. The only reason you should have $0 for your total is that all your products are priced at $0.