Help me finish a web application

I need someone that can help me finish my web application. It is made with an MS SQL database, MVC/C# code in Visual Studio 2017, JQuery and Umbraco 7. After this project I want the application made available as an app for the smartphone. So that is something to consider when working on this project. The multilingual (Vorto) site is not very large. There are two important pages, where things happen. One is shop where products through a filter can be found and listened and put in the shopping cart. The other is a page where the visitor can compose a product, by selecting options. The application reads and writes audio-files, based on the choices of visitors. It produces an audio file. I need someone that can help me design a smart way for the distribution of these audio files. Perhaps a service on a machine in my office? I want to have a reliable registration-, login- and member-part, based on the members that are already defined in Umbraco. There is some code available already, but I have trouble in getting it to work. The design is not made yet, so it has to be done. I need help with getting - filtered - data to the browser in the smartest and fastest way (Angular/Ajax?) The UI is already functional, it needs to connect to the backoffice. The shoppingcart needs to be connected to payment-methods - first of all PayPal - later more like IDeal (Dutch). I want a simple Dashboard in Umbraco to handle the sales that are made and the actions that are needed. Design is not important here. I also want the code I made to be reviewed and optimized, where needed. So what I am looking for is someone that does not have a problem in working with code that is not fully professional (yet). Someone that is prepared to understand the heart of this application. Someone that can give me advise where needed - not in the last place about the design.