public HttpResponseMessage RetriveDocument(Int64 merchantId,Int64 contractId, int documentTypeId)
 {
     IList<DocumentsModel> response;
     using (DocumentTier dT = new DocumentTier())
     {
         response = dT.RetrieveDocuments(merchantId,contractId, documentTypeId);
         return this.Request.CreateResponse(HttpStatusCode.OK, response);
     }
 }