Service operation is unknown for BulkDataExchange calls

[boboci9]

Hi,
I am trying to do a BulkDataExchange call with no luck. I enter the correct operation type but I still keep getting. Did anyone manage to do a BulkDataExchange call? Could you tell me what am I doing wrong?

Thanks in advance!!

'Bad response status code 500 <?xml version=\'1.0\' encoding=\'UTF-8\'?><errorMessage xmlns="http://www.ebay.com/marketplace/services"><error><errorId>2000</errorId><domain>CoreRuntime</domain><severity>Error</severity><category>Request</category><message>Service operation  is unknown</message><subdomain>Inbound_Meta_Data</subdomain><parameter name="Param1"></parameter></error></errorMessage>' 

var eBayAPI = require('ebay-api');
static startDownloadJobRequest(requestParams){

        return new Promise(function (resolve, reject){

            eBayAPI.xmlRequest({
                serviceName : 'BulkDataExchange',
                opType : 'startDownloadJob',

                devId: eBayParams.devId,
                certId: eBayParams.certId,
                appName: eBayParams.appName,
                sandbox: eBayParams.sandBox,
                authToken: requestParams.token,

                params: {
                    'downloadJobType': "SoldReport"

                }
            }, function(error, result) {
                console.log("startDownloadJobRequest",error, result);
                if(error)
                    reject(error);
                else{
                    resolve(result);
                }
            });

        });
    }
}