Create customer feedback / ticketing management system

I am looking for someone to either create or customize a support ticketing system. There are 1000's of ticketing systems out there, but they are over featured and I want one that is SIMPLE. As an admin: - I can create users who can submit tickets. each user is allowed to submit a fixed number of issues per month. Users are subscription based, and their account must be validated via a paypal or any other payment method. - Admin can add users who have access to open tickets, they respond to them and close them. Once the ticket is open, the system will send an email to the person assigned. - System will send an email every 6 hours to remind about open tickets. As a user: - Once subscribed -payment verified- a user can submit tickets. - Each ticket will have issue description, category and a checkbox if URGENT - User can upload a file (txt, doc, or image) I created the same feedback submission system with a Google Document, and its not very hard to create .. its an easy ticketing system I just want this to be linked to a subscription system with login management I will send the Google Form to the right developer once I sense the seriousness ....