Not sure if this is it.. but I'll give it a crack.
You have Dictionary<string, object>
.. yet here:
{ "request", // missing "object" part..
{ "name", "Piece of Cake" },
{ "description", "Virtual chocolate cake to fill your virtual tummy" },
{ "price", "10.50" },
{ "currencyCode", "USD" },
{ "sellerData", "user_id:1224245,offer_code:3098576987,affiliate:aksdfbovu9j" }
}
Perhaps try changing it to this:
{ "request", new Dictionary<string, object>() { // another dictionary.
{ "name", "Piece of Cake" },
{ "description", "Virtual chocolate cake to fill your virtual tummy" },
{ "price", "10.50" },
{ "currencyCode", "USD" },
{ "sellerData", "user_id:1224245,offer_code:3098576987,affiliate:aksdfbovu9j" }
}
}