data storage api

I am reselling data storage and I have a basic html website that I need to add an API to which has been given to me by the reseller company. The api documentation states "we have exposed a SOAP XML web service that can be used to manage user accounts. Each web service request requires a unique API key that we have assigned to you, this key should be kept safe as it allows us to track you usage falls within our terms of service. Each web request will return a status code indicating success or the reason of failure. Should the request succeed you can expect a record to be returned for the data you requested, if however it failed your application will need to handle this." There is an API key but then the documentation states "Create your client - Depending upon you language of choice, some IDE's offer automated SOAP proxy generation. We have included an example C# client to help you get up to speed with the services availiable. Call a method availiable on our web services using your API key. Documentation for each method can be found in the following API reference." There is then an example of a C#.NET 3.5 Console Client I have built the basic website, but need to add the api, along with a payment method that automates the process from a client choosing a particular service, paying for it then being setup on the server that the API relates to. I was assuming that this would be a simple problem to solve which is why I have the budget set fairly low, If you think you can help me out and the budget does not fall within that below, then still please contact me.