What we need to be done is: Before we had the coupon system where we can input a large number of codes, our system worked like any ordinary system. We assigned one coupon for everyone (it was called Universal Coupon). We still have those old files if you need.
What the system should do
• Assign a coupon code for all the users (same number for all)
• It can only be used once per user
• Expire automatically after a period of time
• This has to work alongside with our existing coupon system