crowd source /contest website

I need a website built, including design. I would prefer you use a wordpress cms but feel free to suggest anything... - Members must be able to sign in via Facebook and other popular social media platforms. - Must be able to take payments - Support Membership plans The site: 2 categories of users ( customers and freelancers) A site where customers can post a contest, and freelancers can apply to the contest. Freelancers can upload file and submit their contest on site, and communicate with customer on the project page Admin panel: Admin can moderate contest, suspend or delete member Admin can manage payments and contents Must have full documentation! THIS IS A MUST! Mile stone won't be set until i see satisfactory evidence of work