User Registration system in php

We assume that when the user is created, it creates folder of the user on the server (adduser command). The email goes to the user with confirmation of account created and credentials to login to the webbased system. Deafult space provided to user per account is 1 GB. For addtional space, they need to pay as per their needs. We assume there will be some kind of rate chart or subscription or pre-defined size of usage will be available in the system for user to select for additional space. All the created users should receive mail in 48 hours with confirmation and with the approval from the system. If confirmation is not received in 48 hours the particular user details will be deleted from database permanently and user need to sign up again. After login, user will have following features: My Account - See the account information and upgrade option which will redirec to different pacakges to choose from. User can pay either through credit card / paypal or bank transfer (we assume bank transfer is offline process and admin has to approve the payment receipt to upgrade the account, manually). Packages will be of duration of 30 days based on calendar month and each month credit will be managed by the system. Upload backup - User will upload the backup file. Backup history - Maintain version of the back up with notes and "restore" option which will download the back up file on user's machine. Invoices - User will see the invoices raised and can download the pdf invoices. Also the credit notes are maintained in PDF form which can be downloaded. Termination - Each backup with have start date / expiry date till which user can use the backup files. After reaching the expiry date, user need to request reactivation. Administrator will have following features: User management Subscription Packages (Product) management Invoices & Credit note management Gift Card managment Settings