protected void Refund_OnClick(object sender, EventArgs e)
{
RefundRequestBuilder refundBuilder = RefundRequest.GetBuilder();
RefundRequest refundRequest = refundBuilder
.SetMerchantId(Config.MERCHANT_ID)
.SetMerchantKeyId(merchant_key_id.Value)
.SetMerchantTransactionId(merchant_transaction_id.Value)
.SetPayzippySaleTransactionId(payzippy_sale_transaction_id.Value)
.SetHashMethod(hash_method.Value)
.SetRefundAmount(refund_amount.Value)
.SetRefundReason(refund_reason.Value)
.SetRefundedBy(refunded_by.Value)
.SetUdf1(udf1.Value)
.SetUdf2(udf2.Value)
.SetUdf3(udf3.Value)
.SetUdf4(udf4.Value)
.SetUdf5(udf5.Value)
.Build(Config.SECRET_KEY);
string jsonResponse = WebClient.DoRefund(refundRequest.GetRequestParams(), Config.API_REFUND);
this.Context.Items.Add("refund_response", jsonResponse);
this.Server.Transfer("RefundResp.aspx");
}