Magento Unique Code Voucher Redemption Development

This project has been posted a few times thanks to time wasters, if you cannot do this job DO NOT BID FOR IT!! We would like to get our Magento website to allow customers to enter a unique voucher number on the site to redeem a product(s) and then allow the customer to complete the purchase by getting the customer to pay for a flat delivery fee and enter shipping details on website. A 3rd party website allows online shoppers to purchase items on their website and once purchased provide the customers with a unique voucher code e.g. VOD-VZ4PKRMK9HV and link to our Magento website. It is on our website that we need to enter the above codes and have the customer pay a flat delivery rate ($10) and enter their shipping details. The custom code should allow us to enter all the unique codes (generated by the 3rd party website) and match each code to a product on the Magento site using some type of import process via a .csv file. Currently the Magento version is 1.5.0.1 but the solution should be compatible with 1.6.x.x and future versions and also have a clean backend import process and a natural customer retrieval process on the front-end. In summary... 1. Import .csv file from 3rd party containing unique voucher codes and matching SKU using Magento backend. 2. Customer will purchase product from 3rd party website and is emailed a unique voucher code and URL e.g. Unique Code - VOD-VZ4PKRMK9HV - Retrieval URL = [login to view URL] 3. Customer should be able to enter unique code on ([login to view URL]) and enter the code where the product is discounted to $0 & go through the normal checkout process to pay the $10 flat delivery rate and enter shipping details. Please Note: NO initial milestone payment will be offered, complete the whole job and you will be paid for it but don't waste my time.