BigCommerce to Saasu Windows Service c# .NET

Looking for a .NET software developer to design and build a Windows Service to synchronise data between BigCommerce eCommerce and Saasu online accounting software via web-service API. You do not need to know the Saasu API as we can supply the .NET library and support for it. The applicant must have experience with the BigCommerce API as delivery of the project is required in 1 - 1.5 weeks, so there's no time for learning on the job. Please see attached image which outlines what needs to be synchronized. Must be a fixed price quote with no extensions or increases, so please quote accordingly. Please supply examples of work with the BigCommerce API. Generic messages and bids which do not address our requirements will be discarded.