Need a website like Upwork with many of the same features

I need a website and script like Upwork with many of the same features (see list of features below).Must be responsive design. Must have a good back end / admin section to manage all features. Developr must have experience with building a similar [login to view URL] back end. And must deliver a stable and bug free website before payment is made. Please let me know how long it will take you to complete this project. And what code will be used (php?) Here is a list of most of the features: Login with facebook Join as worker or Join as employer (one account cannot be both) 3 level of membership (free, basic, platinum - with different monthly cost + different commission levels 10%, 8%, 5% ) Unlimited Categories and sub categories Search for projects Post a project + with paid upgrades like featured project, hidden project, rush project Bidding system Escrow or wallet (funds management) Payments approved by Admin (after 15 days) Private messaging system (with file upload) Dispute management Project flagging Admin can send messages to all accounts Rating / feedback for both worker and employer Banner ads display Here are some additional features that can be quoted separately Time tracker app for hourly workers (takes random screenshots) Suspicious word detector (swear words + trying to provide email addresses) Email related jobs to users by category (ei: notify logo jobs to logo designers ) Invite freelancers to bid on your job Ban IP addresses Tell a friend about our site The website will marketed to the people of the caribbean islands (this does not effect the development of the site, only stating our target market)