Build website and Application connected

Only experienced developers needed. We want to build a website for Research writing, Where we will offer writing services. For that reason we need a website with attractive graphics and have all the options which we require. ( I will provide the front end examples). In addition, I also need back end software through which we can communicate with users. There will be multiple back end acces such as Customer support representative access, Manager access and Admin access with the different options such as CSR can only talk to customer no and limited access, Manager will have other additional information and Admin will have all the control. In addition, website should be connected to the portal where writers will make their accounts and manager or admin can assign the task to the Writer( accounts). Also we want the payment intergration through which customer can place order and make payment. So we need website plus application connected to the Andriod or IOS system. Further details will be provided to the correct person after bidding. Only bid if you can accept challeging work, in fair amount.