Alsalaam Aleykum.
All you have to do is to respond to the error. I mean change the date format so the json can parse it to the web service.
your code should look like this:
var o = new Object();
o.Price = "56";
o.Reason = "Tea";
var followupDate = "17-12-2013";
o.Date = new Date(followupDate);
o.Date = "\/Date("+o.Date.valueOf()+")\/";