User registration and verification hotspot (PHP,MySQL, Paypal API)

We looking for someone to develop an easy to use frontend for hotspot registration (PHP). The Mysql database and backend is allready in place. We would need the following functionalities:
Module One (free account)
User registration form with input vallidation, check if user exists, check if mobilenumber is allready used => group with some default values set in a conf file and post to new row in Mysql DB => Ask the customer to confirm his mobile number => send customer SMS with validation code, username and password => client enters validation code (3 attempts) => update field in DB so that the account shows as active. => Pass login info to hotspot page

Module Two (payed account)
User registration form with input vallidation, check if user exists, check if mobilenumber is allready used => show product options => take payment trough Paypal express checkout => successful /rejected pages => group with default values set in conf file and insert row in DB => Ask client to verify mobile => Send username and password to the client Pass login info to hotspot page

Upgrade (free-> payed) / add aditional month
User login form + recuperate password => Show product options take payment trough Paypal express checkout => successful /rejected pages => update row in DB.

All the pages need to have a language selection. Translations stored in language files.