Fix issues in an Online Store cs-cart 3.0

购物网站修改 基于cscart3.0的购物网站。 寻找最好熟悉cscart的开发人员。做完通过测试付款。 背景介绍： 一个用户有个资金账户，还有一个费用/优惠账户（比如负数$-5就是费用，正数$5就是优惠） 有点像用户的积分。后台管理员可以增加减少。 网站现在存在的问题： 1. 结算页面选paypal支付的时候没有把费用/优惠算进实际支付，选其他支付没有问题。 2. 支付提交后，我的订单看到的支付和实际支付不相符，主要是没有把费用/优惠算进来。后台也是。 3. 结算页面有两个价格的显示需要调整。 4. 费用/优惠账户是一次性强制结清，所以支付提交以后要清0，比如本来$-5, 实际支付就加5块，提交以后费用/优惠账户为0。这个规则类似积分，订单取消要恢复回来。 现在的问题是费用/优惠的值是固定不变的，除了管理员在后台可以修改。 5. 这些问题改正后要求通过测试，不会带来新的问题，系统功能正常运行。 6. 工作包括为改正这些问题，server上的更新和配置（如果有的话），就是期望的结果要在线的网站正常运行，而不只是给我看自己配置的测试的网站有没有问题。 7. 开发人员可能需要了解为什么要这个改动，我有一个2页的说明文档，逻辑很简单。 Background: 1. Chinese online store based on the cs-cart 3.0. 2. register user has a balance account and a coupon account. 3. user can pay the bill using the balance in balance account. 4. the value in coupon account can be positive or negative. For example if administrator set value 5 to the user, next time when user purchase, the total amount will be deducted by $5. if admin set value as -5, when user purchase, the total amount will be added $5. after submit, the value becomes 0. but if the order is cancelled, the value in coupon account should be restored. what's the issues: 1. when choose paypal for payment, the value of coupon account is not counted in. It looks fine when choose the other payment methods. 2. After submit the purchase, the order is appeared in my order list. But the price there is not correct. Main problem is that the value of coupon account is not counted in. 3. 2 prices of display need to be adjusted. It is for display only. 4. After submit the purchase, the value of coupon account should become 0. However if the order is cancelled. The value should be restored in coupon account because the purchase/order is not completed. 5. Make sure to fix any issue due to the changes and passes testing.